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Here is another issue of private line! Thanks again.
THIS IS THE TEXT OF PRIVATE LINE NUMBER 5 -- VOLUME 2, NO. 1
This issue contains four photographs and 16 illustrations,
including some nice exploded diagrams of COCOTS. Send me $5.00 if
you want the hardcopy version. My address is:
private line
5150 Fair Oaks Blvd. #101-348
Carmichael, CA 95608
$24 a year for 6 issues. Price goes to $27 on July 1, 1995.
Mexican and Canadian subscriptions are $31 and overseas
subscribers have to pay $44 :(
I. Editorial Page
II. Updates and Corrections
III. Cell Phone Basics, Part 1
IV. The Roseville Telephone Museum
V. Telecom Related Magazines and Newsletters
I. EDITORIAL PAGE
1. Damien Thorn has agreed to be the technical editor for
private line. Damien has written for Tap and 2600. He now writes
a great column called Full Duplex Communications for Nuts and
Volts. Damien brings more than 15 years of practical, hands on
hacking experience to private line. Let me explain a little about
what he'll be doing for the magazine and what it means to you.
2. Damien won't be checking every technical fact in my
writing or in this magazine, any more than I will check on his
writing. Instead, he'll help me with questions that I can't
answer. I can't tell you, for example, which cell phones are the
easiest to work on and why. He can. I can tell you in general
about cell phone theory and operation but I can't tell you much
about real field experiences. He can. His advice will help me make
fewer mistakes and keep private line more interesting and more
practically grounded. In addition, he's also open to the idea of
writing a column on a regular basis. I am very happy that he has
signed on.
3. What will this magazine cover in the future? I intend to
write general pieces about specific subjects. An issue on PBX's,
one on outside plant equipment, another on business telecom
equipment and so on. I will not write any specific hacking pieces
myself. That's for any reader of the magazine to do. I could put
two months of effort into a piece about hacking ROLMs but what
good would that do someone who doesn't know about PBX operation to
begin with? Someone that doesn't know a port from a pier? Reader
submitted articles may be as specific as you like. But I'll keep
my pages and my articles oriented toward beginners.
4. Today is January 1, 1995. The start of a new year. It's
odd to think that these words won't be read until March. In
reality, my deadline is only three or four weeks before the cover
date. But you have to get each page done when you can. It's one of
many oddities that I am dealing with for the first time. Magazine
distribution is certainly another. A newssrack for a small
magazine is like a consignment stand. Practically every magazine
will be bought the real question is how many. You're doing well
if 25% of your magazines go unsold. I explained the costs of
producing private line last issue but I didn't figure in the cost
of returns. Instead of $1.18 a copy, therefore, the true cost is
more like $1.47. Quite a difference. On the positive side, it
looks like I'll have at least 1200 copies printed up of this issue
instead of 600 for the last. That will lower the per unit cost
quite a bit. On the other hand, the better cover for this issue
will make costs go up. And first class mail rates have also gone
up. Oh, well. It feels like I am reinventing the wheel in learning
all these things. When I don't have the time to learn them to
begin with. What's a solution?
5. Well, the solution might be easy if I had a great deal of
money. I could hire staff and advertising people. Then I'd go back
to writing and research. But I don't have the money nor would I
really want to change the character of the magazine by hiring a
paid staff. Perhaps a better idea might be to organize a loosely
structured publishing house for alternative technical magazines.
Six or seven 'zines using the same printer to lower costs, sharing
the same advertiser list and promoting each other's magazines with
free ads in each others publications. Nothing too formal or
involved. More like an association. No dues or fees. We could all
keep in touch with fax machines, the mail and the internet. A
quick check of Factsheet5 reveals several technologically oriented
magazines: 2600, 2600 Connection, 3W, Short Circuit and
Historically Brewed. Throw in all the electronic zines on the net
that don't go into hardcopy and you've got quite a few people who
aren't in the mainstream writing about tech. I don't have the time
to explore this right now but feel free to write if you have any
thoughts along this line. Lastly, I want to thank all my new
readers, especially those subscribers who signed up without seeing
a copy of private line first. That takes faith. In return, I'll
try to put out the best magazine I can, something with articles
you'll be interested in. The mailbox and the electronic door are
always open . . .
Tom Farley
Carmichael, California
privateline@delphi.com
II. UPDATES AND CORRECTIONS
6. The internet patent connection got turned off for a few
weeks in January. Try it again if you were disappointed before.
Internet Multicasting Service and the Patent and Trademark Office
were apparently involved in a turf war, with the PTO doing the
instigating. There's hope, though, for the future. Bruce Lehman,
commissioner of the Patent Office, told the IEEE Spectrum that his
agency intends to put the entire patent collection online by the
end of the decade. Hot damn. That means the text of all patents
dating back to 1790. Wouldn't it be possible, however, to get text
and illustrations at a web site? The patents are simple black and
white line drawings. Speaking of web sites, I didn't include the
PTO's in last issue. It is: http://www.uspto.gov/
7. Def Con III will be held at the Tropicana Hotel in Las
Vegas on August 4th, 5th, and 6th. Speakers will talk on the
fifth and sixth. Get there. The Tropicana Hotel is located at 3801
Las Vegas Blvd. South, Las Vegas, Nevada, 89109. Rooms are $65 for
a single or a double Monday through Thursday. Rates climb to $90
for a single or double from Friday to Sunday. Ask for the Def Con
III convention to get those rates when you call. The Tropicana is
at (800) 4689494 or (702) 7392448 (Fax). Yes, Dark Tangent knows
that those rates are expensive. That's why he encourages everyone
to keep track of developments as the con draws near. Keep up on
details and you'll find cheaper motels, people to drive with or
people to crash with. The ftp site is: ftp.fc.net /pub/defcon.
Subscribe to the mailing list by sending email to the following:
majordomo@fc.net. Put the following statement in the body of your
message: subscribe dcannounce. This will put you on the mailing
list and you will receive updated information on a regular basis.
DT's voice mail is 07008264368 from a phone with AT&T LD. His
email address is dtangent@defcon.org. There's also a bulletin
board at Alliance Communications +1 612251 2511. Or write him at
2709 E. Madison #102, Seattle, WA, 98112. That will also get you
on a list. I do not want any excuses from any of you for not going.
You have the whole spring and summer to save up. You have months
and months to schedule an entire week off. Which is what you'll
need to really enjoy yourself. And you will enjoy yourself. I
won't be speaking but I will ask Dark Tangent about setting aside
an hour or two for telephone talk. Anyone interested in that could
just show up at a certain place at a certain time. No big deal. I
wrote at length about Def Con II in private line #3. Please,
please try to get there. I'll be writing a little more on this as
the con draws near.
8. I just got a copy of Public Communications Magazine. It's
the trade magazine that covers customer coin operated telephones
most. A careful reading clears up many mysteries surrounding the
wiley COCOT. Even the ads are interesting. The inside cover of the
November issue, for example, has a Mars Electronic International
ad that shows their MS16 electronic coin validator. It's an
electronic beastie that checks each coin deposited into a COCOT.
While these units were originally designed to guard against fraud,
some telcos have been installing them in an apparent attempt to
prevent red boxing. Unlike a COCOT, a telco payphone doesn't check
every coin deposited during a conversation. It usually just checks
the initial deposit. It can't do much more since it's just a dumb
box of relays. No memory or intelligence. It sends tones to the
central office to indicate a coin deposit. A red box simulates
those tones. A coin validator can help stop this if added to a
telco payphone. There are other ways for a telco to stop red
boxing. One of my readers reports that GTE in some parts of the
midwest has gone away from ACTS or automated coin toll service.
They're now routing 1+ calls to the operator. You can still try
boxing but you lose your anonymity. Public Communications also
mentions some other interesting things. Ever notice the housing on
these COCOTs? They look like a telco brand (W.E.) but cheaper?
Quadram Telecom probably makes them. And who supplies the boards
for these so called smart phones? The boards that let the COCOT
total coins, rate calls and provide an ACTS like voice to tell you
how much they are ripping you off for? Leading suppliers are
Protel, maker of the BB and 2000 board, Intellistar, Elcotel and
Intellicall. These fit on a chassis as illustrated on page 48.
And the locking mechanisms? The most sophisticated is from Medeco
High Security Locks, Inc. It's part of a whole system of key
management. Check out the March 7, 1994 issue of Design News for
more information on this coin box lock. Look for this system to
come into wider use in the future.
9. Speaking of the future, the telephone industry is going
nuts over debit cards. And I mean nuts. Even Teleconnect is going
overboard. Public Communications and Telecard World are fueling
the fire but it is the private payphone owner and the card seller
that will shove these things into our lives. What's worse is the
talk of putting debit card payphones in a neighborhood near you.
No coins accepted, thank you. Coinless phones were limited before
to airports, train stations or highway rest stops. Places where
you had lots of other phones to choose from or no other phones at
all. One example is Ameritech's LobbyLine indoor coin phone. You
call with a calling card or debit card. Or you call collect or
bill to a third party. The present debit phones, though, are being
discussed as a replacement to the omnipresent COCOT. The reason?
Pure greed. Protel's president, Jerry Yachabach, says that more
than 70% of the cost of maintaining payphones is due to coin
related functions. He reasons that the industry should find a
substitute for coins. Great. His comments go along with pictures
of two expensive looking credit card phones. No doubt Protel will
make big bucks by selling these things. And what about the rest
of the trade? What do they think? Eric Stebel, Managing Editor of
Public Communications, nearly drools when he writes "And talk
about vandalism and theft switching to a debit card payphone
would virtually eliminate that. When was the last time you heard
of someone blowing up a payphone just for the fun of it? No, most
vandals have an ulterior motive to get to your payphone's coin
box. And just think of the float money your company could make off
of lost or unused cards. Heck, some people would even buy your
debit cards as a collectible and never use them." Hey, Eric, float
this! Let's go over some of these terms.
10. The most common form of debit card is the prepaid long
distance calling card. Or talk and toss. Industry types call it
centralized debit card technology. You pay for a certain amount of
long distance in advance at a retail store. In return you get a
card. Such as the "AT&T PrePaid Calling Card" available at Office
Depot. It has an 800 number and a calling card number on the back.
The pictures on the front, in part, drive collector mania. These
can be anything from Satan to Santa. Let's say you want to call
Germany. You call a number like 1800357 PAID. Your call is routed
to a PBX somewhere. Industry favorites for prepaid cards are the
NACT LCX 120C from National Applied Computer Technologies and the
Harris Digital Systems 20/20 switch. Harris has an entire system
called Protocall to handle prepaid debit cards. Their 20/20 switch
is called a NGC for some strange reason when it's part of
Protocall. In any case, the card seller's switch gets your call.
What then? Next step is to enter the calling card number. Could be
anything. Like 533 442 5968. The automated attendant tells you the
value on your card. It then tells you to dial your number. Your
call now goes out from the PBX to the Federal Republic. The robot
comes back on after your call to tell you how much you have left
on your card. You're now free to make another call or hang up.
It's a pretty neat system and you can't beat the anonymity when
you're calling from a payphone. The Tonya Harding Gang did have
their toss and talk card calls monitored. But that's because the
FBI was already watching.
11. What are the economics of all this? Here's a quotation
from December's Teleconnect. This article had the happy title
"Cash Cow": "Imagine you have a 100 store chain. You sell one
$20 prepaid calling card per day per store. You bring in $60,000
a month. ($3,000 cards). You sell calls for 35 cents a minute.
Your call cost is 24 cents a minute. 15% of the cards are not
active (breakage). Your first month's operating margin is
$24,000. Your first year's operating margin is $486,300. Where
does the 24 cents a minute come from? You pay seven cents a
minute for inbound 800 calls. Eight cents a minute for calls
going out. Staff and space two cents. Equipment is five cents.
Printing of cards is half a cent. Dedicated T1s [the leased line
running from the telephone company to the switch] are one and a
half cents a minute. The name of the game is volume. Without
volume you can't get your prices down enough." Well, you know that
AT&T can get costs down. Yet they charge 60 cents a minute for a
call within the United States on their card. Much of that must go
to places like Office Depot that actually sell the card. But it's
still an expensive service. Remember, too, that a one minute and
one second call will get you dinged for two minutes. The other
kind of debit card is one with a magnetic stripe. You swipe these
in the reader of a debit card payphone. Many countries have this
service. Some telcos are playing with it now. Want to call home
from the Quickie Mart? Buy a card from the store or go to a
vending machine. Just like a BART card. Calls go directly to their
destination once the payphone approves the card. The Public
Utilities Commission in each state will probably require that 911,
800 numbers and 10X codes can be dialed without a card. Whether
the COCOT actually allows those calls is another story. You may
also hear about a debit card with an integrated circuit built in.
This is chip technology. The chip itself maintains the account
balance of the card. VISA and Mastercard are coming out with these
soon. You'll be able to make small transactions of all sorts,
including phone calls. I think, though, that calling them debit
cards is wrong. Chip cards are based on credit and not on money
put up front. That makes them a credit card and not a debit card.
12. I will be printing letters in upcoming issues. Tell me if
you don't want your name printed. I want to welcome
CONSUMERTRONICS aboard as private line's first paid advertiser.
I've heard many good things about John Williams' company and I am
happy to have them along. Speaking of advertising, my rates are
now $100 for a full page, $50.00 for a half and $25.00 for a
quarter. See what you missed by not signing on earlier? All
subscribers get free classified ads of twenty five words or less.
Thanks again to all my new subscribers!. I now have 39 paid
subscriptions! Life is good. . .
III CELLULAR TELEPHONE BASICS, PART 1 -- BY TOM FARLEY
13. Welcome to the world of cellular telephony. It's a
fascinating place. Used phones prices are falling rapidly. It's
time to experiment or at least to read up. Let's look at the big
picture first. Telephone over radio is nothing special or unusual.
Long distance radio telephony dates back to at least 1927, with
the introduction of overseas service on short wave between the
United States and Great Britain. AT&T and the British Postal
Office put that project on the air after four years of
experimenting. They expanded it later to communicate with Canada,
Australia, South Africa, Egypt and Kenya as well as ships at sea.
This service had fourteen dedicated channels or frequencies
eventually assigned to it. The main transmitter was at Rugby,
England. [1] Cables and satellites have replaced radio telephone
for nearly all long distance use but many ships still use it.
Radio amateurs on short wave still handle noncommercial telephone
calls over short wave. These patches often handle emergency
traffic.
14. Local, noncommercial radio telephony has also been going
on for years, possibly since the 1950's. Enterprising radio
amateurs wired simple telephone interfaces to their base stations
long before any direct connection to Bell System equipment was
allowed. These home built kits preceded today's sophisticated
autopatches. An autopatch is, essentially, a remotely controlled
phone. You activate and control one from afar with your radio's
DTMF keypad. This could be a 6 meter, 2 meter, 70 cm or even a 1.2
GHz handheld or car mounted rig. You can then make calls from
anywhere that you can key up the autopatch.
15. Car mounted mobile telephones carried out local
commercial traffic for decades. Companies like Motorola still make
them. It's an excellent choice for areas not well served by
cellular. Cellular service may cover 90% of urban areas, but it
only reaches 30% to 40% of the geographical area of America. Many
people refer to mobile telephone by just saying IMTS, which stands
for Improved Mobile Telephone System. It's the newest form of
mobile radio. [2] Most IMTS equipment operates in the UHF band. A
centrally located transmitter and receiver serves a wide area with
a relatively few frequencies and users. It's the same concept that
taxi fleets and tow truck companies use to dispatch vehicles. Most
areas allow you to dial out directly from your car, however, there
are still places where the operator comes up on frequency to place
the call for you. [3] A single customer could drive 25 miles or
more from the transmitter, however, only one person at a time
could use that channel.
16. This limited availability of frequencies and their
inefficient use were two main reasons for cellular's development.
The breakup of the Bell System in 1984 allowed real cellular
development to begin. The key to the system is the concept of
frequency reuse as depicted in the upper right. Let's look at
that as well as some basic cell phone theory.
II Basic Theory and Background
17. Cell phone theory is simple. Executing that theory is
extremely complex. Each cell site has a base station with a
computerized 800 megahertz transceiver and an antenna. This radio
equipment provides coverage for an area that's usually from two to
ten miles in radius. Even smaller cell sites cover tunnels,
subways and specific roadways. The amount of area depends on
topography, population, and traffic. The MTSO decides which cell
and which frequencies in that cell should carry your call. How
does it do that?
18. Your telephone's signal strength declines or
increases as you move toward or away from a tower. The nearest
base station constantly reports this signal strength to the MTSO.
The mobile switch transfers your call to another cell when your
signal level drops to a predetermined point. This handoff usually
occurs automatically when the switch determines that another
cell's transmitter can provide a better, stronger connection. You
may drive fifty miles, use 8 different cells and never once
realize that your call has been transferred. Let's look at some
basics of this amazing technology.
19. The FCC allocates frequency space in the United States
for many services. Some of these assignments may be coordinated
with the International Telecommunications Union but many are not.
Much debate and discussion over many years placed cellular
frequencies in the 800 megahertz band. The FCC also issues the
necessary operating licenses to the different cellular providers.
Cellular development began in earnest after the Bell System
breakup in 1984. The United States decided to license two carriers
in each geographical area. One license went automatically to the
local exchange carriers. The LECs. The other went to an
individual, a company or a group of investors who met a long list
of requirements and who properly petitioned the FCC. Cellular
parlance calls these LECs wireline carriers. Each company in each
area took half the spectrum available. What's called the "A Band"
and the "B Band." There's no real advantage in having either one.
The nonwireline carriers usually got the A Band and the wireline
carriers got the B band. Depending on the technology used,
however, one carrier might provide three times the connections a
competitor does with the same amount of spectrum.
20. Cell phone frequencies start at 824.04 MHz and end
at 893.7 MHz. [4] That's 69.66 megahertz worth of radio frequency
spectrum. Quite a chunk. By comparison, the AM broadcast band
takes up only 1.17 megahertz of space. This band, however,
provides only 107 frequencies to broadcast on. Cellular may
provide thousands of frequencies to carry conversations and data.
This large number of frequencies and the large channel width
required for each channel account for the large amount of spectrum
space. For example, AT&T's Advanced Mobile Phone Service or AMPS
uses 832 channels that are 30 kHz wide. It's the most common
system right now. AMPS, though, has been replaced with NAMPS in
crowded cell site areas. NAMPS stands for Narrowband Advanced
Mobile Service. It's a Motorola technology. It produces 2412
narrow channels. A NAMP's channel is 10 kHz wide. AMPS, NAMPS and
Hughes' ENAMPS are all FM based, analog systems. Digital systems
like CDMA and TDMA provide even more channels in the same space.
CDMA, in particular, could provide 20 times the number of
frequencies that an AMPS system can. Let's back up a little before
we drown in a sea of acronyms.
21. I mentioned that a typical cell channel is 30 kilohertz
wide compared to the ten kHz allowed an AM radio station. How is
it possible, you might ask, that a one to three watt cellular
phone call can take up a path that is three times wider than a
50,000 watt broadcast station? Well, power does not necessarily
relate to bandwidth. A high powered signal might take up lots of
room or a high powered signal might be narrowly focused. A wider
channel helps with audio quality. An FM stereo station, for
example, uses a 150 kHz channel to provide the best quality sound.
A 30 kHz channel for cellular gives you great sound almost
automatically, nearly on par with the normal telephone network.
That's what's impressive about Motorola's NAMPS. The base station
uses a special frequency control circuit to keeps calls exactly
on frequency. No wavering or moving off frequency to destroy a
call's quality. Things should sound fine with this narrow band
_if_ everything is working right.
22. I also mentioned that the cellular band runs from 824.04
MHz to 893. 97 MHz. In particular, cell phones use the
frequencies from 824.04 MHz to 848.97 and the base stations
operate on 869.04 MHz to 893.97 MHz. 45 MHz separates each
transmit and receive frequency within a cell. That keeps them from
interfering with each other. Getting confusing? Let's look at the
frequencies of a single cell for a single carrier. Maybe that will
clear things up. For this example, let's assume that this is one
of 21 cells in an AMPS system:
Cell#1 of 21 in Band A (The nonwireline carrier)
Channel 1 (333) Tx 879.990 Rx 834.990
Channel 2 (312) Tx 879.360 Rx 834.360
Channel 3 (291) Tx 878.730 Rx 833.730
Channel 4 (270) Tx 878.100 Rx 833.100
Channel 5 (249) Tx 877.470 Rx 832.470
Channel 6 (228) Tx 876.840 Rx 831.840
Channel 7 (207) Tx 876.210 Rx 831.210
Channel 8 (186) Tx 875.580 Rx 830.580 etc., etc.,
(Each cell has at least 15 frequencies or channels)
23. The cellular network assigns these frequency pairs
carefully and in advance. The layout is confusing since the
pattern is non-intuitive and because there are so many numbers
involved. Don't get too caught up with exact frequency assignments
unless you want to go further. [5] Speaking of numbers, check out
the sidebar. Channels 800 to 832 are not labeled as such. Cell
channels go up to 799 in AMPS and then stop. Believe it or not,
the numbering begins again at 991 and then goes up to 1023. That
gives us 832. Why offset at all? Cellular is not like CB radio.
Citizen's band uses the same frequency to transmit and receive. A
push to talk setup. Cellular provides full duplex communication
like nearly all modern radios. It's more expensive since the
mobile unit and the base station need the circuitry to transmit on
one frequency while receiving on another. But it's the only way
that permits a normal, back and forth, talk when you want
to, conversation.
24. Some Important Frequency Terms Okay, so what do we do we
have? Three things: 1) Cell phones transmit on certain, dedicated
frequencies, 2) base stations transmit on certain, dedicated
frequencies and 3) a certain amount of bandwidth separates these
frequencies. Let's get even more specific. We call a cell site's
transmitting frequency the forward channel. A forward channel
contains everything you hear since it is the cell site that
transmits it. The cell phone's transmitting frequency, by
comparison, is called the reverse channel. There's more. Certain
channels carry only data. We call these control channels. They,
too, have a forward and reverse frequency. This control channel is
usually the first channel in each cell. It's responsible for call
setup. Getting confusing? Let's go back to our friendly cell site
for an example.
[TABLE]
25. The first channel is always the control channel for each
cell. You'll have 21 control channels if you have 21 cells. Calls
get setup on these. A call gets going, in other words, on the
control channel first. The MTSO then assigns a normal channel to
carry the conversation. The voice channels and the control channel
may handle signaling during the actual conversation. A single
call, therefore, involves two kinds of forward and reverse
channels. One for voice and data and one for data only. Makes it
hard to follow, doesn't it? But there are real benefits to
figuring it out. A phone's ESN number, for example, is only
transmitted on the reverse control channel. A person poaching ESNs
need only monitor one of 21 frequencies. They don't have to look
through the entire band. I'll use the terms reverse control
channel and reverse voice channel to keep these terms separate
from now on. One last point at the risk of loosing everybody.
You'll hear about dedicated control channels, paging channels, and
access channels. These are not different channels but different
uses of the control channel. Let's clear up the confusion by
looking at call processing. We'll start out with AMPS since it's
the most common system and because TDMA uses the AMPS protocol to
first set up calls. Even a CDMA carrier uses an AMPS system in the
background to carry calls from non-digital phones. We'll also
touch on a number of new terms along the way.
III Call Processing
26. Let's look at how cellular uses data channels and voice
channels. Keep in mind the big picture while we discuss this. A
call gets set up on a control channel and another channel actually
carries the conversation. The whole process begins with
registration. It's what happens when you first turn on a phone but
before you punch in a number and hit the send button. It only
takes a few hundred milliseconds. Registration lets the local
system know that a phone is active, in a particular area and that
it can now take incoming calls. What cell folks call pages. The
local system then notifies, in theory, the entire nationwide
cellular network that this phone has come on line. Registration
begins when you turn on your phone.
Registration -- Hello, World!
27. A mobile phone runs a self diagnostic when it's powered
up. Once completed it acts like a scanning radio. It searches
through its list of forward control frequencies, trying to pick
the one with the strongest signal. The nearest base station
usually provides that. The phone then transmits information to
identify itself on the corresponding reverse control frequency.
The mobile sends its phone number, its electronic serial number
and its home system ID. Among other things. The cell site relays
this information to the mobile telecommunications switching
office. The MTSO, in turn, communicates with different databases,
switching centers and software programs.
28. The phone gets registered with the local system if
everything checks out. It can now take incoming calls since the
system is aware that it is in use. The mobile then monitors a
paging channel while it idles. All idle phones monitor this
initial paging channel or IPCH. It's usually channel 333 for the
non-wireline carrier and 334 for the wireline carrier. [6] Only
larger systems have multiple paging channels. Again, this is a
data based, forward control channel, transmitted by the cell site.
What's different about a paging channel is that it cuts across the
entire cellular service area. It's transmitted by each base
station, even if that frequency isn't part of a cell's group of
fifteen or sixteen. A mobile first responds to a page on the
reverse control channel of the cell it is in. The MTSO then
assigns yet another channel for the conversation. But I am getting
ahead of myself. Let's finish registration.
29. Registration is an ongoing process. Moving from one
service area to another causes registration to begin again. Just
waiting ten or fifteen minutes does the same thing. It's an
automatic activity of the system. It updates the status of the
waiting phone to let the system know what's going on. The cell
site can initiate registration on its own by sending a signal to
the mobile. That forces the unit to transmit and identify itself.
Registration also takes place just before you call. Again, the
whole process takes only a few hundred milliseconds.
30. AMPS uses frequency shift keying to send data. Just like
a modem. Data's sent in binary. 0's and 1's. 0's go on one
frequency and 1's go on another. They alternate back and forth in
rapid succession. Don't be confused by the mention of more
frequencies. Frequency shift keying uses the existing carrier
wave. The data rides 8kHz above and below, say, 879.990 MHz. Read
up on modems and FSK and you'll understand the way AMPS sends
digital information. Data gets sent at 10 k bps or 100,000 bits
per second from the cell site. Quite impressive if we're talking
about a modem on a land line. But we aren't. Cellular uses a radio
link, a very high frequency signal that's subject to the vagaries
of its band. Things such as billboards, trucks, and underpasses
can deflect a cellular call. So the system repeats each part of
each digital message five times. That slows things considerably.
Add in the time for encoding and decoding the digital stream and
the actual transfer rate can fall to as low as 1200 bps. [7]
Remember, too, that an analog wave carries this digital
information, just like most modems. It's not completely accurate
to call AMPS an analog system. AMPS is actually a hybrid system,
combining both digital and analog signals.
Getting a Call -- The Process
31. Okay, your phone's now registered with your local system.
You get a call. It's just MCI security, wondering about all those
conference calls to the mideast. You laugh and hang up. As you
drive off to pick up another shipment of weapons, you marvel at
the process of getting a call. What happened? Your phone
recognized its mobile number on the paging channel. That's usually
the forward control channel. The mobile responds by sending its
identifying information once again to the MTSO, along with a
message confirming that it received the page. The system responds
by sending a voice channel assignment to the cell you are in. The
cell site's transceiver gets this information and begins setting
things up. It first informs the mobile about the new channel, say,
channel 10 in cell number 8. It then generates a supervisory audio
tone or SAT on the forward voice frequency. What's that?
32. An SAT is a high pitched tone that acts like a marker.
The mobile tunes to its assigned channel and it looks for the
right supervisory audio tone. Upon hearing it, the mobile throws
the tone back to the cell site on its reverse voice channel. We
now have a loop going between the cell site and the phone. This
verifies that the mobile is on the right frequency. No SAT means
no good. The cell site can fine tune the phone's reception with
the SAT. It can also use it roughly determine the phone's
location, since it takes a certain time for the signal to make a
go around. The cell site releases or unmutes the forward voice
channel if the SAT gets returned. It follows that by sending a
digital signal on the FVC. This signal alerts the mobile to an
incoming call. That action, in turn, causes the mobile to take the
mute off the reverse voice channel. The mobile sends an audio
tone to the cell site confirming that it got the alerting message.
The system then produces a ringing sound for your caller while
your phone rings. But let's go back to the SAT for just a moment.
33. I said that a mobile looks for the right supervisory
audio tone. AMPS uses three named frequencies: SAT 0: 5970 Hz,
SAT 1: 6000 Hz, and SAT 2: 6030 Hz. Three different markers. Why?
Spacing cell site frequencies carefully avoids interference. It's
the same way with SATs. Call setup is ongoing in each cell. Using
several frequencies makes sure that the mobile is using the right
channel assignment. It's not enough to get a tone on the right
forward and reverse frequency the system must get the right
channel and the right SAT. Two steps. Incorrect SATs cause havoc
in the cellular bands. This tone is transmitted briefly but
somewhat continuously during a call. You don't hear it since the
signal lasts less than 300 ms. and because it's muted during
transmission. The mobile, in fact, drops a call after a certain
amount of time if it looses the SAT connection.
34. Well, enough about the SAT. I mentioned another tone
that's generated by the mobile phone itself. It's called the
signalling tone or ST. Don't confuse it with the SAT. You need the
supervisory audio tone first. The ST comes in after that. It's
necessary to complete the call. The mobile produces the ST,
compared to the SAT which the cell site originates. The signaling
tone is a very high audio frequency tone that you can't hear.
Maybe your dog can but not you. It's 10 kHz tone. The mobile
starts transmitting this signal back to the cell on the forward
voice channel once it gets an alerting message. Your phone stops
transmitting it once you pick up the handset or otherwise go off
hook to answer its ringing. Cell folks might call this
confirmation of alert. The system knows that you've picked up the
phone when the ST stops. AMPS uses signalling tones of different
duration's to indicate three other things. Cleardown or
termination means hanging up, going on hook or terminating a call.
The phone sends a signalling tone of 1.8 seconds when that
happens. 400 ms. of ST means a hookflash. Hookflash requests
additional services during a conversation in some areas.
Confirmation of handover request is another arcane cell term. The
ST gets sent for 50 ms. before your call is handed from one cell
to another. Along with the SAT. That assures a smooth handoff from
one cell to another. The MTSO assigns a new channel, checks for
the right SAT and listens for a signalling tone when a handover
occurs. Complicated but effective and all happening in less than a
second.
Origination -- Making a call--
35. Making a mobile call uses many steps that help receive a
call. The same basic process. Punch out the number that you want
to call. Press the send button. Your mobile transmits that
telephone number, along with a request for service signal, and all
the information used to register a call to the cell site. The
mobile transmits this information on the strongest reverse control
channel. The MTSO checks out this info and assigns a voice
channel. It communicates that assignment to the mobile on the
forward control channel. The cell site opens a voice channel and
transmits a SAT on it. The mobile detects the SAT and locks on,
transmitting it back to the cell site. The MTSO detects this
confirmation and sends the mobile a message in return. This could
be several things. It might be a busy signal, ringback or whatever
tone was delivered to the switch. Making a call, however, involves
far more problems and resources than an incoming call does.
36. Making a call and getting a call from your cellular phone
should be equally easy. It isn't. Originating a call from a mobile
presents many problems for the user and the carrier. Especially
when you are out of your local area. Incoming calls don't present
a risk to the carrier. Someone on the other end is paying for
them. The carrier, however, is responsible for the cost of
fraudulent calls originating in its system. Most systems shut
down roaming or do an operator intercept rather than allow a
questionable call. I've had close friends asked for their credit
card numbers by operators in order to place a call. Can you
imagine giving a credit card number or a calling card number over
the air? You're now back at a payphone, just like the good old
days. Cellular One has shut down roaming "privileges" altogether
in New York City, Washington and Miami at different times. But you
can go through their operator and pay three times the cost of a
normal call if you like. So what's going on? Why the problem with
some outgoing calls? We first have to look at some more terms and
procedures. We need to see what happens with call processing at
the switch and network level. This is the exciting world of
precall validation.
37. We know that pressing send or turning on the phone
conveys information about the phone to the cell site and then to
the MTSO. A call gets checked with all this information. There are
many parts to each digital message. A five digit code called the
home system identification number (SID or sometimes SIDH)
identifies the cellular carrier your phone is registered with.
For example, Cellular One's code in Sacramento is 00129. Go to
Stockton forty miles south and Cellular One uses 00224. A system
can easily identify roamers with this information. The "Roaming"
lamp flashes if you are out of your local area. Or the "No
Service" lamp comes on if the mobile can't pick up a useable
signal. This number is keypad programmable, of course, since
people change carriers and move to different areas. You can find
yours by calling up a local cellular dealer. Or by putting your
phone in the programming mode. [8]. This number doesn't go off in
a numerical form, of course, but as a binary string of zero's and
ones. These digital signals are repeated several times to make
sure they get received. The mobile identification number or MIN
is your telephone's telephone number. MINs are keypad
programmable. You or a dealer can assign it any number desired.
That makes it different than its electronic serial number that we
discuss next. A MIN is ten digits long. A MIN is not your
directory number since it is not long enough to include a country
code. It's also limited when it comes to future uses since it
isn't long enough to carry an extension number either. [9]
38. The electronic serial number or ESN is a unique number
assigned to each phone. One per phone! Every cell phone starts out
with just one ESN. This number gets electronically burned into the
phone's ROM, or read only memory chip. A phone's MIN may change
but the serial number remains the same. The ESN is a long binary
number. Its 32 bit size provides billions of possible serial
numbers. The ESN gets transmitted whenever the phone is turned on,
handed over to another cell or at regular intervals decided by the
system. Every ten to fifteen minutes is typical. Capturing an ESN
lies at the heart of cloning. You'll often hear about stolen
codes. "Someone stole Major Giuliani's and Commissioner Bratton's
codes." The ESN is what is actually being intercepted. A code is
something that stands for something else. In this case, the ESN. A
hexadecimal number represents the ESN for programming and test
purposes. [10] Such a number might look like this: 82 57 2C 01.
39. The station class mark or SCM tells the cell site and the
switch what power level the mobile operates at and what
frequencies the phone uses. The cell site can turn down the power
in your phone, lowering it to a level that will do the job while
not interfering with the rest of the system. The SCM also tells
the switch if your phone is voice activated. That information, in
turn, affects the way the MTSO handles signalling a VOX phone.
40. The switch process this information along with other
data. It first checks for a valid ESN/MIN combination. You don't
get a dial tone unless your phone number matches up with a
correct, valid serial number. You have to have both unless,
perhaps, if you call 911. The local carrier checks its own
database first. Each carrier maintains its own records but the
database may be almost anywhere. These local databases are
updated, supposedly, around the clock by two much larger data
bases maintained by Electronic Data Systems and GTE. EDS maintains
records for most of the former Bell companies and their new
cellular spin offs. GTE maintains records for GTE cellular
companies as well as for the Cellular One group, a consortium of
many different companies. Dial tone will not be returned unless
everything checks out. They try to supply a current list of bad
ESNs as well as information to the network on the 27,000 new
cellular users coming on line every day.
41. A local caller will probably get dial tone if everything
checks out. Roamers may not have the same luck if they're in
another state or fairly distant from their home system. A roamer's
record must be checked from afar. Many carriers still can't agree
on the way to exchange this information or how to pay for it. A
lot comes down to cost. A distant system may still be dependent on
older switches or slower databases that can't provide a quick
response. The so called North American Cellular Network is an
attempt to link each participating carrier together with the same
intelligent network/system 7 facilities. Still, that leaves many
rural areas out of the loop. A call may be dropped or intercepted
rather than allowed dial tone. In addition, the various carriers
are always arguing over fees to query each others databases. Fraud
is enough of a problem in some areas that many systems will not
take a chance in passing a call through. Yet the fraud is fueled
in part by lax network security. It's really a numbers game. How
much is the system actually loosing? How much is prevention?
Preventive measures may cost millions of dollars to put in place
at each MTSO. In any case, the outlook is not good for roaming.
Yet the ability to drive anywhere and call from anywhere was a
main reason to move away from the old mobile telephone system. You
used to have to call ahead to say that you would be visiting a
distant city. An operator then had to make arrangements for your
phone to be recognized by the local system. Well, Cellular One
throughout December and January of last year was asking visiting
cell phone callers to do just that before coming to New York City.
Such progress!
42. In the next issue I'll write a shorter article that
highlights TDMA and CDMA. I intend to have a resource list of part
suppliers and publications. I'll also bring you some current
information on cell fraud, including a look at Cellular Technical
Service's Project Blackbird, a radio "fingerprinting" system
designed to identify cloned phones. A similar system is being
turned on in N.Y.C so the article should be interesting . .
NOTES
[1] Hawks, Ellison. Popular Science Mechanical Encyclopedia:
How It Works Popular Science Publishing Co., Inc. New York. 1943
87
[2] Fike, John L. and George E. Friend. Understanding Telephone
Electronics SAMS, Carmel 1990 268
[3] West, Gordon. Mobile 2Way Radio Communications, Master
Publishing Company, Richardson, 1991 41
[4] Macario, Raymond. Cellular Radio: Principles and Design,
McGraw Hill, Inc., New York 1993 61 ISBN 007044301 A good book
that's fairly up to date and in print. Explains several cellular
systems such as GSM, JTACS, etc. as well as AMPS and TDMA. Details
all the formats of all the digital messages. No CDMA About
$40.00.
[5] Cellular Security Group is advertising free cellular frequency
charts. You may want to call first. They're at (508) 7687486. The
address is 106 Western Avenue, Essex, MA 01929. Sending a few
dollars may help . . .
[6] Damien Thorn "Cellular Telephone Programming: Focusing on
Fundamentals" Nuts and Volts Magazine (December, 1992) 23
[7] Noll Introduction to Telephone Systems 123 (I've lost the cite
on this one I'll have it next issue)
[8] Thorn, ibid, 2 see also "Cellular Lite: A Less Filling Blend
of Technology & Industry News" Nuts and Volts Magazine (March
1993)
[9] Crowe, David "Why MINs Are Phone Numbers and Why They
Shouldn't Be" Cellular Network Perspectives (December, 1994) I
give all the information on Crowe's newsletter on page 52.
IV THE ROSEVILLE TELEPHONE COMPANY MUSEUM ------------------------
The Photographs on the Opposite Page
43. The upper left hand photograph shows the interior of a
typical magneto wall set. Turn a crank and you generate enough
power to signal the operator. Batteries provided the line current
needed to talk. Note the pad beneath the batteries used to soak up
the occasional acid spill.
44. The upper right hand photograph shows an Automatic
Electric, Type 1 test board that was one of four in service in
Roseville from 1956 to 1984. Tests of the local loop often
required one person at the test board and one person in the field
to actually perform the adjustments. Many coin line tests are
marked at this board.
45. The lower left hand photograph shows an operator toll
switchboard in use from 1959 to 1981. Local and long distance toll
calls were handled at this A.E. Model Type 31C cord toll board.
Several boards were in use at any one time.
46. The lower right hand photograph shows a detail of the
step by step switch. The entire mechanism is nearly six feet tall
by six feet wide. All photographs by Little Sheeba"
Text of Article -----------
"The notion of a museum springs from the passion for
collecting, which is deeply rooted in human nature. All
civilizations, from the most primitive to the most advanced,
share the desire to accumulate objects that are beautiful,
costly, rare, or merely curious."
47. The Roseville Telephone Company's museum in downtown
Roseville, California is a marvelous collection of telephone
technology. More than that, it reflects the history of an
independent, progressive telephone company. Any telecom enthusiast
should take the time to travel there, visit for an hour or two and
engage in wondering, reflection and curiosity. What will you find?
300+ telephones. 12 switchboards. A test board and a toll board.
Friendly telephone people to talk to. And best of all the pride
of the museum a working step by step switch.
48. Step by step or Strowger switches were the mainstay of
switching in rural and small town America for over forty years.
I've described stepper operation in previous issues but I never
thought I did a good job of explaining the process. Seeing one
work is a great way to understand it. A large, open case contains
the switch. Three phones are mounted on the left side of the case
and three on the right. You can call from one phone to the other
and in so doing observe all the action. Pick up a handset and go
off hook. A selector jumps into action as you start dialing. Watch
the wipers revolve as they search for a contact. Something's
moving with every digit you dial. Hang up and everything resets
itself with a satisfying clunk. Will you comprehend Strowger when
you see it? Maybe not. But you should see it anyway. A stepper is
like a Swiss watch with its insides revealed. You may not follow
the function of each lever, sprocket and cam but you can
appreciate its design and construction. And you can hear the
wonderful clicking, chattering sound that steppers make, the sound
that old switchmen get nostalgic about. The Roseville Telephone
Company people will happily explain its operation. They'll even
show you how the TraceaMatic works. It's a simple device once used
to trace calls on a step switch.
49. The magneto powered cord switchboard is also interesting.
Switchboards like these acted as a telephone company's central
office before automation. This board dates back to 1914, the first
year of RTC's operation. A small crank on the bottom right hand
side allowed an operator to ring a customer's phone. Let the RTC
people demonstrate how the board rings some of the phones on
display. Vary the cranking at the switchboard and you vary the
ring. That's important since RTC had more than ten subscribers on
some party lines. What Roseville Telephone called farmers' lines.
Each customer needed a distinctive ring, since it was the only way
each party could tell if the call was for them. Party lines lasted
until 1986 when the last open wire farmer line was retired.
There's a nice exhibit that tells the story. That display includes
square poles, insulators and samples of the wires. The two parties
on that retired line, by the way, had their old monthly rate
grandfathered in. To this day they pay less than $3.00 a month for
phone service.
50. There's 4,000 square of exhibit space at the museum. The
curator of the museum, Bob Parsons, says that Roseville Telephone
will expand this to 8,000 feet within just a few years. Some of
this new area will include outside plant equipment as well as a
working open wire demonstration. They're even going to outfit an
old telephone repair truck from the 1920's with a complete set of
tools.
51. Thinking of going? I've had friends from Stockton and
the San Francisco bay area say that it's well worth the drive.
Plan to spend an hour to an hour and a half in the museum. Have
lunch afterwards and help out the flood stricken economy. There
are plenty of antique stores in Roseville in case someone with you
gets bored. As well as one of the major train switching yards on
the West Coast. Speaking of antiques, Roseville has a dealer who
specializes in telephones. American Antiques and Collectables is
located inside the building at 106 Judah Street. The old phones
are expensive but you can handle them and look at them closely.
52. I tried to find out about telephone museums and
collections in the United States but I've come up with only a
small, incomplete list. Please write if you find something
interesting in you area. Local antique dealers might help you. Go
in to a large one and ask who collects telephones. A telephone
collector will know if there are any museums or displays in the
area. You might even be able to wrangle a tour of a private
collection. Want to know more? Fagen's A History of Engineering
and Operation in the Bell System: The Early Years 1875 1925
explains older phones and systems. It concentrates on Western
Electric equipment but it is still invaluable on understanding
early phones, PBX's, toll boards and switchboards.
53. Roseville is located 15 miles northeast of Sacramento,
California Take Interstate 80 to the Atlantic Street off ramp.
Head north into Roseville. Atlantic becomes Vernon downtown. The
address of the museum is 106 Vernon. It is open on Saturdays only
from 10 to 4. Look for the only building with a cell tower on
top.
V. TELECOM RELATED MAGAZINES AND NEWSLETTERS
54. Welcome to the telecom related magazine list of private
line. This is an update to the list that first appeared in issue
Number 5. I think it is the best magazine list on the Internet. I
hope to update this every two months or so. Addresses are for
subscriptions and samples. I didn't include editorial addresses to
save space. Quoted material comes from a magazine's masthead or
from a reader's comments. Let me know if you find any mistakes in
this list or if you find a magazine that I should be aware of.
55. Some of these magazines will give you free subs if you
take it third class and are "qualified" to have it. My advice is
to ask for a sub, fill out their form and let them make the
decision. Who knows? Maybe the magazine needs more subscribers so
that they can charge higher ad rates. I personally am always
willing to pay for a sample copy.
56. See what happens after you write in. Then start filling
out product information cards in the magazines that arrive. Be
specific. The trick is to get a low cost flow of information into
your mailbox. Really broke but still interested? Ask for their
writers' guidelines along with a sample. Or ask for a media kit.
Dummy up some letterhead at Office Depot and call yourself a
consultant if you have to. But I just use my real name. That's
worked so far.
2600: The Hacker Quarterly
General hacking. Some of the best telephone hacking articles in
print. 10 years worth of back issues available.
2600 Enterprises, Inc.
P.O. Box 752
Middle Island, NY 11953
(516) 751-2600
2600@well.sf.ca.us
Quarterly. U.S. and Canadian subscriptions: $21 individual and
$50. Overseas: $30 individual and $50 corporate in US Funds.
Advanced Wireless Communications
A newsletter from the Telecom group. They do say that they won't
charge for a sample. And they did send me a nice catalog of their
expensive publications.
Telecom Publishing Group
1101 King St. Suite 444, Box 1455
Alexandria, VA 22313-20555
1-800-452-8011
$492. Bi-weekly with a fax alert.
America's Network
Formerly Telephone Engineer and Management, a well respected
industry magazine. "I tried to find info for you on TE&M since I
used to get it free as a kid. Loved it! Looked for it on my last
dumpster mission. Alas, all I got from the spoils were a couple
issues of Telephony."
Advantstar Communications
131 West First Street
Duluth MN 55802-2065
Twice a month. $44 a year to United States addresses. A sample is
$4.95.
Antique Telephone Collectors Association Newsletter
A publication of the ATCA. It contains news of their organization
as well as interesting articles on the history of telephony. It
also has classified ads, some with pictures, from members looking
to buy and sell old phones, phone parts, books, phone memorabilia
and other collector items. Fascinating reading. The newsletter
comes free with your membership. Write for a sample as well as for
a membership application.
ATCA
Ann Manning, Office Manager
P.O. Box 94
Abilene, KS 67410
(913) 263-1757
The newsletter is monthly. Dues are $30 a year to U.S. members,
paid on a calendar basis. People joining mid-year pay pro-rated
dues of $2.50 a month. There is a one time fee of $5.00 for new
members.
AT&T Technical Journal
Not as technical as the old B.S.T.J. nor understandable as the
old Bell Laboratories Record., the AT&T Technical Journal does
come up with some fascinating articles. No. 73 was on AT&T
switches. The 5ESS-2000 and the 4ESS were both reviewed along with
a lengthy discussion of how cellular and PCS calls are switched.
Circulation Group, Room 3C-417
AT&T Bell Laboratories
600 Mountain Ave.
P.O. Box 636
Murray Hill, N.J. 07974-0636
(908) 582-4019
Six times a year. $55 domestic. $11.00 for single copies. They may
have two years of back issues available but some editions are sold
out. Best to write first for info on back issues and subscribing.
Bell Labs News
Nicely done tabloid sized, 6 page newspaper that's published bi-
weekly. Closed subscriber list. Limited to employees of AT&T . I
got a copy from a subscriber but you may want to try the person
below:
Linda Crockett, Editor
Room 3C-420 A
AT&T Bell Laboratories
600 Mountain Avenue
P.O. Box 636
Murray Hill, NJ 07974-0636
(908) 582-4739
attmail!crockett
Blacklisted! 411
"The Official Hacker's Magazine". A nicely done magazine out of
southern California. It's well worth looking for. You'll probably
want to subscribe if you enjoy 2600 or my magazine.
P.O. Box 2506
Cypress, CA 90630
(310) 596-4673
Quarterly. $20 a year. $5.00 for a sample.
Cabling Business Magazine
"The Only Telecommunications Copper and Fiber Optics Cabling and
Wiring Magazine for Voice, Data, and Image." These people seem a
little too eager to give you a subscription. Wouldn't even tell
me the price of a sample or sub over the phone. They insisted on
sending a free copy. In addition, the publication is very
practical and interesting. Write for this one!
Cabling Business Magazine
P.O. Box 496177
Garland TX 754049-6177
(214) 328-1717
Call Center
A call center is a place that takes a customer's calls. It might
be a catalog sales center or a cable TV company's order
department. Interesting enough to check out. "Ten Ways To Foil a
Hacker" was a good, non-hysterical article on fraud.
Call Center
1265 Industrial Highway
Southampton, PA 18966
1-800-677-3435
MCI Mail 627-4700.
Monthly. US: 12 issues for $14. Canada: $20.
Cellular Business
"This rag sucks and doesn't contain much more than fluffy press
releases from the manufacturers of phones and accessories. No
technical information, and they ran an article on cellular fraud
that was grossly inaccurate and belonged in a Sunday newspaper
supplement. I subscribed, and then refused to send them the $39
they wanted for a subscription. Just glossy garbage." Your
editor, though, thinks that it really is worth a look, they seem
to be getting better.
Cellular Business
Intertec Publishing Corp.
P.O. Box 12901
Overland Park, KS 66282-2901
(913) 341-1300
Monthly. $24 a year to qualified subscribers. Call for free
sample.
Cellular Marketing
Another publication that I haven't seen but one that David Crowe
recommends. He says it is trying to take on a more technical
focus. Write for a sample.
Argus Circulation Center
P.O. Box 41528
Nashville, TN 37204
$29 for a U.S. sub and $39 for a Canadian or Mexican subscription.
Cellular Network Perspectives
Expertly done, professional newsletter. David Crowe focuses on
networks, protocols and general cellular concepts, rather than on
exact technical details. It gives you the big picture without any
corporate slant.
Cellular Networking Perspectives
2636 Toronto Crescent NW
Calgary, AB T2N 3W1 Canada
(403) 289-6609
(403) 289-6658 FAX
71574.3157@compuserve.com
Monthly. $150 a year for small business and educational customers.
$250 otherwise. All back issues available He'll mail or fax you a
copy of "IS-41 Explained" if you like.
Computer Telephony
Driven by ads and corporations. Same folks as Call Center and
Teleconnect. Some interesting articles on occasion. A recent
article by Mitel predicts the death of PBX's as we understand them.
They're giving away subs so you might as well sign up.
Computer Telephony
1265 Industrial Highway
Southampton, PA 18966
1-800-677-3435
1015032@mcimail.com 70600.2451@compuserve.com
Electronic Design
A real find. Features articles occasionally on telecom. Goldberg's
article on PCS, for example, was a better read than a similar
article that ran about the same time in the expensive IEEE
Personal Communications.
Electronic Design, A Penton Publication
Penton Publishing Subscription Lockbox
P.O. Box 96732
Chicago, Ill 60693
Supposedly $105 a year. Write for a sample -- you should be able
to wrangle a free sub from them.
FCC Report
Another newsletter from Telecom.
Telecom Publishing Group
1101 King St. Suite 444, Box 1455
Alexandria, VA 22313-20555
1-800-452-8011
$591. They say they don't charge for a sample. People on the phone
are sometimes confused.
Fiber Optic News
Newsletter. "Covers management and marketing of optical fibers and
laser technology"
Phillips Business Information, Inc.
12051 Seven Locks Road
Potomac, MD 208564
1-800-777-5006
Weekly. 50 times a year. 10 pages. $697 a year. $37.50 for a
sample.
Full Disclosure
Glen Roberts puts out this interesting, newspaper like
publication. It deals with many electronic privacy issues but it
has some nice telephone articles from time to time. I see it only
rarely on newsstands. Ask your magazine dealer to order it through
Fine Print Distributors.
First Amendment Press, Inc.
8129 N. 35th Ave., Suite 134
Phoenix, AZ 85051
Monthly. $29.95 for 12 issues. Canadian subscriptions add $15.00.
For all other countries add $25.00 per twelve issues.
Global Telephony
Another one from Intertec. I haven't called for prices yet.
Intertec Publishing Corp.
P.O. Box 12901
Overland Park, KS 66282-2901
(913) 341-1300
IEEE Communications Magazine
Occasionally interesting telephone pieces. I read it from time to
time at a university libary.
IEEE Service Center
445 Hoes Lane
Piscataway, N.J. 08855-13311
(908) 981-0060
j.milizzo@ieee.org
Monthly. $23 to members, $135 to non-members, single issue copies
are $10 to members and $20 to non-members.
IEEE Personal Communications
"The Magazine of Nomadic Communications and Computing" Winter 1994
edition had lots of stuff on the development of PCS protocols.
Cutting edge information if you can understand it or afford it.
IEEE Service Center
445 Hoes Lane
Piscataway, N.J. 08855-13311
(908) 981-0060
e.wilber@ieee.org
Quarterly. $80 a year to non-members. A single copy to non-members
costs $20.
Innovations
This is Protel's own quarterly newsletter. They're the largest
COCOT maker in the country. It's small (4 pp) but well done and
it's free. Greg Hogan, National Accounts Manager, does a good job
explaining the NANP or North American Numbering Plan in issue 7.
Send a postcard requesting it to:
Teresa Frueh Blocher
Protel Inc.
4150 Kidron Rd.
Lakeland, Fl 33811-1274
BTW, she wants your name, company name, and your daytime phone
number. Yeah, right.
ISDN News
Another expensive newsletter from Phillips.
Phillips Business Information, Inc.
12051 Seven Locks Road
Potomac, MD 208564
1-800-777-5006
25 times a year for $597 a year. $35 for a sample. They'll send
you a free brochure on it if you want one.
Land Mobile Radio News
Newsletter. They'll send you a free brochure on it.
Phillips Business Information, Inc.
12051 Seven Locks Road
Potomac, MD 208564
1-800-777-5006
Weekly. 50 times a year. 12 to 14 pages an issue. $597 a year. $35
for a sample.
Local Competition Report
Another newsletter from Telecom.
Telecom Publishing Group
1101 King St. Suite 444, Box 1455
Alexandria, VA 22313-20555
1-800-452-8011
$425 yearly. Comes out every two weeks. They say they don't
charge for a sample.
Local Telecom Competition
Newsletter. They'll send you a free brochure about it if you want
it.
Phillips Business Information, Inc.
12051 Seven Locks Road
Potomac, MD 208564
1-800-777-5006
Bi-weekly. 25 times a year. 12 to 14 pages an issue. $597 a year.
$35 for a sample.
Microwave Journal
" . . . I get more technical info about the direction and
technology of cellular from one issue of RF Design News or
Microwave Journal than I could from a whole year of Cellular
Business."
Horizon House Publications, Inc.
P.O. Box 850949
Braintree MA 02185-0949
(617) 356-4595
Monthly. Domestic, one year, $67.00, two year $110, foreign $120
one year, two year subscriptions $230, back issues (if available)
and single copies, $8.00 domestic and $17.00 foreign.
Microwaves & RF
Heavy duty publication for the radio engineer.
Microwaves and RF
A Penton Publication
1100 Superior Avenue
Cleveland OH 44197-8101
(216) 696-7000
Monthly. $60 for US subscriptions. Free to qualified individuals.
Mobile Communications
International
Magazine. Haven't seen it.
Central House
27 Park Street
Croydon CRO 1YD
+44 (0)81 686 5654
Monthly. 40 pounds UK, overseas 60 pounds ($120) per year.
Mobile Data Report
Another newsletter from the folks at Telecom.
Telecom Publishing Group
1101 King St. Suite 444, Box 1455
Alexandria, VA 22313-20555
1-800-452-8011
$597. Every two weeks. They say they don't charge for a sample.
Mobile Phone News
Phillips Business Information, Inc.
12051 Seven Locks Road
Potomac, MD 208564
1-800-777-5006
Newsletter. Weekly. 50 times a year. $597 a year. $35 for a
sample. They'll send you a free brochure on it if you want one.
Mobile Satellite News
Phillips Business Information, Inc.
12051 Seven Locks Road
Potomac, MD 208564
1-800-777-5006
Newsletter. Weekly. 50 times a year. $597 a year. $35 for a
sample. They'll send you a free brochure on it if you want one.
Monitoring Times
Grove Enterprises, Inc.
P.O. Box 98,
300 S. Highway 64 West
Brasstown, North Carolina 28902-0098
Monthly. $21.95 in the U.S. and
$32.00 elsewhere. Newsstands.
Nuts and Volts
Arguably better than Popular Electronics at its height. Great ads
and even better articles. Damien Thorn's cellular articles were
especially good. I usually find Nuts and Volts at a ham radio
store. Write for a sample.
Nuts and Volts Magazine
430 Princeland Court
Corona, CA 91719
(909) 371-8497
74262.3664@compuserve.com
Monthly. 3d class: $17.00 a year or 2 years for $31. 1st class:
$34.00 for one year in the USA. $5.00 for back issues.
On the Line
"The National Publication of the California Payphone Association".
A regional publication that does cover national issues. Another
resource for COCOTs. No reader service cards but worth getting.
California Payphone Association
c/o On the Line
2610 Crow Canyon Rd., Suite 150
San Ramon, CA 94583
(510) 855-3880
Six times a year. $25 a year. Send $5.00 and you'll get a sample.
Or call them up and use your social engineering skills. . .
Outside Plant
Outside plant is an old telephone term for everything outside of
the switching center. It's a nice publication but I doubt you are
going to get a free sub -- I'm still working on them to give me a
discount or to trade subs.
Practical Communications, Inc.
P.O. Box 183
Cary, Illinois 60013-0183
One year $30 domestic, one year for Canadian addresses is $64 US.
Phone +
Another COCOT related magazine. A good place to get more
information on a hard to research topic. Write or call for a free
sample.
Phone +
Box 5400
Scottsdale, AZ 85261-5400.
(602) 990-1101
15 times a year for $50.00
Popular Communications
The "Telephones Enroute" column written by Tom Kneitel (K2AES) is
very good. Mostly product announcements regarding cellular
equipment but analyzed by someone who knows what they're talking
about.
CQ Publications
76 N. Broadway
Hicksville, NY 11801
(516) 681-2926
Monthly. Domestic rate is $21.50 You can get it from any magazine
dealer.
Premier Telecard Magazine
Another telecard magazine. I haven't seen it. I'd send at least
five dollars for a sample. Or call first
BJE Graphics and Pub., Inc.
P.O. Box 2297
Paso Robles, CA 93447
(805) 547-8500
A $30 subscription gets you the mag, two telecards and a telecard
calendar for 1995.
private line
"A journal of inquiry into the telephone system" Okay, you didn't
think that I'd leave mine out, did you? The finest, self indulgent
nonsense about the telephone system in print today.
private line
5150 Fair Oaks Blvd. #101-348
Carmichael, CA 95608
privateline@delphi.com.
$24 a year for six issues. Goes up to $27.00 July, 1. $4.00 for a
sample. Back issues $5.00. Text of back issues are on line at:
etext.archive.umich.edu/pubs/Zines/PrivateLine
Public Communications Magazine
A hoot. COCOTs and more. The November, 1994 issue featured an
article on how raising a local payphone call to $.35 will benefit
everyone. Really. I got a free sample by calling the 800 line.
My sample came with a form for a free subscription which they did
give me.
Public Communications
P.O. Box 6246
Syracuse, NY 13217-7920
1-800-825-0061
Radio Communications Report
"For cellular phone information, my favorite is a weekly tabloid
called Radio Communications Report. It has every thing that
Phillips newsletters have (plus a lot more) at 1/10 the price.
It's also a lot better than the glossies like Cellular Business
for following current events in the business."
RCR Publications Inc.
777 East Speer Blvd.
Denver, C0 80203
1-800-678-9595
Semi-monthly. 1 year $39; 2 years - $59. Wouldn't tell me the
sample price -- insisted on mailing me a free copy.
RBOC Update
Worldwide Videotext
P.0. Box 138
Babson Park, Boston MA
(508) 477-8979
Monthly newsletter. $150 a year
Report on AT&T
Newsletter. "Reports on all activities of AT&T" Focuses on "AT&T
and its bloody turf battles."
Telecom Publishing Group
1101 King St. Suite 444, Box 1455
Alexandria, VA 22313-20555
1-800-452-8011
Twice a month. $697 a year with a fax alert. They say they will
send you a free sample if you are interested.
Satellite Times
Grove Enterprises, Inc.
P.O. Box 98,
300 S. Highway 64 West
Brasstown, North Carolina 28902-0098
(704) 837-9200
grove@mercury.interpath.net
Bi-monthly-- $19.95 in the U.S.
and $26.00 elsewhere .
State Telephone Regulation Report
Telecom Publishing Group
1101 King St. Suite 444, Box 1455
Alexandria, VA 22313-20555
1-800-452-8011
Twice a month newsletter. $535 a year. They say they will send you
a free sample if you are interested.
TeleCard World
"America's Leading Magazine for the Telephone Card Industry" Very
interesting. Your place to find O.J. calling cards. They'll send
you an old issue as a free sample.
Telecard World
P.O. Box 6246
Syracuse, NY 13217-7920
1-800-825-0061
$36.00 yearly for US subscriptions.
Telecom Gear
"The National Marketplace To Buy & Sell Telecommunications
Equipment" They focus more on used PBX and office equipment,
rather than telco equipment which Telephone International covers.
15400 Knoll Train
Suite 500 Dallas, TX 75248
(214) 233-5131
Monthly 3d class: $31 a year. They sent me a free sample when I
wrote for information.
Telecommunications: Americas' Edition
The best corporate telecom magazine that I've seen. Same group
that publishes Microwave Journal.
Horizon House Publications
P.O. Box 850949
Braintree, MA 02185-0949
telecom@world.com
Monthly. $67.00 a year US, $120 foreign, single issues are $8 US
and $17 for foreign.
Telco Business Report
Was Telephone Week. Another expensive newsletter from Telecom.
Telecom Publishing Group
1101 King St. Suite 444, Box 1455
Alexandria, VA 22313-20555
1-800-452-8011
Twice a month newsletter. $695 a year. They say they will send you
a free sample if you are interested.
Telecommunications Policy
Academic publication. Policy stuff and more. Explains and comments
on technology to non-engineer university types. Uses side margins
to footnote! Worth looking at but you'll have to search.
Turpin Distribution Services Ltd. Blackhorse Road
Letchworth. Herts SG6 IHN. UK
Nine times a year. Corporate subscriptions: 270 pounds to UK and
Europe, 285 pounds to the rest of the world. Individual: 90
pounds. (Specify Telecommunications Policy when ordering)
Teleconnect
Teleconnect is more practically oriented than most corporate
publications. Available through the Tower chain and at many
newsstands.
1265 Industrial Highway
Southampton, PA 18966
1-800-677-3435 70600.2451 @compuserve.com
12 issues for $15 -- Canada: $30. Retails for $4.00 a copy.
Telemarketing
"The Authority on Inbound, Out bound and Customer Service
Management"
Telemarketing
One Technology Plaza
Norwalk , CT 06854
1 -800-243-6002
Bi-monthly. $49 in the U.S. Call for a sample.
Telephony
Some value because it is timely and widely available. Guest
editorials are good. Lots of product announcements and self
serving press releases.
Telephony
P.O. Box 12976
Overland Park. Kansas 66282-9940
(312) 922-1408
4944254@mcimail .com
Weekly. $45.00 domestic. Single copies are $5.00.
Telephone International
"Published for buyers and sellers of telecommunications equipment
since 1985" This newspaper like publication has display ads and
classifieds. Caters to the telco crowd. Small but interesting
photos of GTD5s, DMS lOOs, etc. in the ads. This may be your best
chance of seeing some inside plant equipment. Fairly easy to get a
free sub.
Telephone International
P.O. Box 3589 -- Hwy. 70 N.
Crossville, TN 38557-3589
(615) 484-3685
Monthly. Domestic is $50.00 for two years if mailed first class.
Ask for a sample.
TeleProfessional
"Effective Marketing Via Telecommunications" I think that
telemarketing is a terrible thing but the technology involved is
fascinating. An easy one to get a free sub from.
209 West Fifth Street Suite N
Waterloo, Iowa 50701 -5420
(319) 235-4473
$39 a year. They were running a $10 subscription promo when I
called. And they happily sent a sample.
Voice Processing Magazine
"The source for applications of computer-telephone integration &
voice automation"
Advanstar Communications
131 W. Birst Street
Duluth, MN 55802
$39 for one year or $59 for two years. $4.95 for a sample.
Washington Telecom News
Phillips Business Information, Inc.
12051 Seven Locks Road
Potomac, MD 208564
1 -800-777-5006
Newsletter. Weekly. 50 times a year. 8 to 10 pages an issue. $597
a year. $35 for a sample. They'll send you a free brochure on it
if you want one.
Wireless
"For the corporate user" . Wireless is the future. This magazine
covers it well with nice articles on many aspects. Good reader
service cards.
Circulation Department: Wireless
Three Wing Drive, Suite 240
Cedar Knolls NJ 07927-1000
(201) 285-1500
Every two months (bi-monthly). Free to qualified subscribers. $30
to US subscribers and $36 for our Canadian and Mexican friends.
They did send me a free sample.
STILL LOOKING!
AT&T Technology,
Common Carrier,
Global Telecommunications,
Tele-Asia,
Telecom and Network Security Review, Telecommunications Journal of
Australia, Telesis,
World Wide Telecom,
Telekom Praxis,
Funkschau,
Commutations and Refutations,
Phillips' Telecommunications Review
Ericsson Review,
Siemens' Telecom Report
Northern Telecom Magazine
See you on the net!
Tom Farley
5150 Fair Oaks Blvd. #101-348
Carmichael, CA 95608
privateline@delphi.com