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Demon Internet Ltd
==================
Gateway House
322 Regents Park Road
Finchley, London, N3 2QQ
0181-371 1234 (Sales - London)
0131-552 0344 (Sales - Edinburgh)
0181-371 1010 (HelpLine)
0181-371 1150 (Fax)
0181-371 1000 (Switchboard)
email internet@demon.net
MODEM.TXT - INFORMATION ON CONFIGURING A MODEM FOR CONNECTING TO THE
INTERNET
Last updated: 19 April 1995
The latest version of this document is available from
ftp.demon.co.uk:/pub/doc/Modem.txt
Contents
========
1. General
2. Essentials
3. Telephone Exchange
4. Internal Modems
5. Which Phone Number
6. Modem and Telephone Leads
7. Serial Chips
8. Speed
9. Trouble Shooting
10. Software and Other Factors
11. Help for Specific Computers
11.0. IBM PC Compatibles running DOS
11.1. OS/2
12. Individual Modem Settings
12.0. Setting up a kind of modem not described below
12.1. Setting Up a US Robotics/Miracom Modem
12.2. Apple Express Modem
12.3. BT NS 2232 M
12.4. Dowty
12.5. Dynalink
12.6. Gateway
12.7. Global Village
12.8. Mistral
12.9. Multitech
12.10. Pace Microlin
12.11. Pace Mobifax
12.12. Racal
12.13. Rockwell chipset modems
12.14. SmartOne
12.15. Supra modems
12.16. Yoriko modems
12.17. Zoltrix
12.18. Zoom modems
12.19. Zyxel
13. Testing
14. Finally
1. General
============
This document will point out some general essentials and advice on
setting up your modem. A section at the end discusses specifics
regarding a DOS setup running the KA9Q NET.EXE program. Due to the vast
combinations of computer and modem setups it is impossible to give
specific help for all types.
Making an Internet (IP - Internet Protocol) connection via a modem is
very different from a standard dial-up connection. Do not assume that
just because you can download from a BBS (and maybe upload) or use other
services that you have your communication (comms) set-up 100% sorted out.
Due to the nature of IP, if you get errors, throughput can be hit very
badly. Under IP information is sent in packets and for maximum speed
these should generally be as large as possible up to a maximum of about
1500 characters. If a packet gets messed up (garbled) its entire
contents will have to be resent - hence a large speed degradation may
occur.
One exception to this is when an interactive sessions are sharing a
TCP/IP link with more voluminous transfers such as NNTP or SMTP. In this
case it can be preferable to have smaller transmission units (Maximum
Transmission Units setting or MTU) so that keystrokes/screen updates will
fit into the data stream with less delay. If a large MTU is used this
can lead to what feels like a jerky or intermittent session.
Enough of the technical parts, there follows some sound advice that
everybody should take note of.
2. Essentials
===============
Correct modem settings:
Full hardware handshaking (CTS/RTS),
Flow control
XON/XOFF (software handshaking) set to off
Settings must be bi-directional where appropriate.
A full specification modem cable (open yours up - if it has
only 3 wires it is no good).
A serial chip that can cope with the high speeds (if using a
high speed modem). Extended memory drivers and Terminate Stay
Residents (TSRs) etc. can interfere with the handling of
interrupts from serial chips.
3. Telephone Exchange
=======================
The Demon Internet Service (DIS) is on modern digital exchanges
so you should have little trouble with ringing tones etc when
connecting to us. If you are on an older exchange, your modem
may not recognise the dialling tone. If this happens, look in
your manual and change the setting that overrides the dial tone
recognition.
Note that when you make changes to a modem's settings you
should always reset the modem first, make the change and then
save the settings. You will need a comms or "terminal
emulation" package such as Telix, Procomm, Window's Terminal, Z-
Term, Microphone etc. Look in your modem manual for
instructions. Mostly you will be able to type ATZ <return> to
reset your modem. On a US Robotics/Miracom modem you could
type:
ATZ Reset the modem
ATX3 Alter a setting
AT&W Write the settings to Non-Volatile RAM (NVRAM)
The last bit (AT&W) is useful as it means that when the modem
is reset, it will remember the settings you have stored.
If going through a private telephone network (or PABX) first,
you will probably need to dial a number such as 9 to get an
outside line. Make sure your dial string has this in. You may
need to separate this from the number to dial by a separator
such as a comma so that there is a pause to give your telephone
system time to give you an outside line:
9,01813434848
4. Internal Modems
====================
Internal modems have the advantage of not having a serial lead
to worry about but the disadvantage of using an extra interrupt
and generally don't have any lights to let you know what is
going on. Ensure that the interrupt on which the modem sits
does not interfere with any others - refer to the setup program
for your computer and your modem manual. This may require
altering a jumper (a small connector) on the main computer
board (mother board) on your computer or on a separate board.
This should be well documented and is well within the scope of
the average user. Ensure that the modem is seated correctly in
the expansion slot.
5. Which Phone Number
=======================
We have multiple Points of Presence (PoPs) - please see
/pub/doc/Demon.txt for details. Thus you will have a choice of
numbers to ring. You may use any of our PoPs at any time.
6. Modem and Telephone Leads
==============================
Your modem lead should be in good condition and preferably not
wrapped in a tight circle or running parallel to high power
cables etc. This will normally only affect longer runs and, as
your cable should be earthed, will not often be a problem. The
cable should be connected securely at both ends as should the
telephone cable. If you suspect your telephone socket may be
causing a problem then test it with a standard plug in
telephone. Use the correct type of modem lead - they vary from
country to country.
7. Serial Chips
=================
The type of serial chip (Universal Asynchronous
Receiver/Transmitter - UART) in use can make a big difference
to comms performance/reliability. At higher speed the computer
can sometimes not service the serial chip fast enough to catch
all of the characters arriving down the line. This problem
increases if running under a multi-tasker such as Windows,
certain memory managers and other TSRs.
8. Speed
==========
Close to every modem user's heart is the speed at which they
can operate. There are two different speeds: the first is the
speed at which a modem can talk to another modem; the second is
the speed at which the modem can talk to its controlling
computer (the DTE rate).
Firstly, we will discuss the connect rate. A V.22bis modem can
connect at a speed of 2,400 bits per second. There are 8 bits
in a byte (a byte is usually one character) so that is a
maximum of 300 characters per second (cps). Due to start and
stop bits, each byte will take 10 bits reducing the speed to
240 characters per second. When running over IP there is a
slight overhead and so you will never see this maximum.
However, as you can (and will) have several things happening at
once, you will be able to make very good use of your available
bandwidth.
Many modems have compression protocols built in to them. MNP/4
and V42 use synchronous connections to provide an error free
connection between modems, saving the start and stop bits.
This gives at least a 20% increase in throughput. V42bis adds
compression, provided that the DTE rate is higher than the
connection rate. This means that when downloading a plain text
(or ASCII) file, it is possible to get faster speeds by
compressing the data. The data is compressed so that the same
information can be encoded in to a smaller space. The
receiving modem will of course unscramble the data for you. If
news normally flows in at say 200 cps, then, on a 2400 cps
link, you have up to 44 cps left at the same time for mail,
telnet'ing, ftp'ing etc. Compression techniques do not work as
effectively on binary files and make very little difference to
pre compressed files (such as .zip, .zoo, .lha etc.).
Note that MNP5 will usually degrade throughput on an IP link
due to the packet based nature of it's compression method.
V42bis does not suffer this problem as it is capable of
optimising itself dependent on the type of data being
transferred.
Now we will discuss the second speed - the speed at which the
modem and computer communicate with each other. This is called
the Data Terminal Equipment (DTE) rate. If you have a slow
modem, e.g. a 2400 baud one without MNP or V42, then it will
probably only work correctly when talked to by the computer at
the same speed. For the facts on your particular modem and
computer you should refer to your manuals. On faster modems
you will only be able to take advantage of some of the
compression features by making the computer talk to the modem
at a faster speed than modem is talking to the remote modem
down the telephone line. Thus you should talk to a 9600 modem
at 19200 or even 38400. You should check the maximum speed at
which the serial port on your modem can talk and then set your
communication package to work at the highest mutually available
speed. Don't forget that without a buffered UART you are
unlikely to sustain reliable high speed comms above 9600 baud.
Please note that we only support modems capable of V22bis
(2400) and upwards. If you have a US Robotics/Miracom HST
modem, you may not get very good throughput in HST mode. In
practice HST mode is fine if FTP'ing from a site without
anything else happening (sending mail etc.) as it works fine in
one direction at a time only.
9. Trouble Shooting
======================
If you are getting garbled characters on the screen then
something is wrong! Garbled characters are often a sign of
mismatched speeds, lack of handshaking or a non-locked DTE
rate. If you get as far as the login prompt but no further
then make sure that your dialler script is working on 8 bit
standard comms: 8 bits, no parity, 1 stop bit. See
/pub/doc/Demon.txt for the full logon script details.
Having checked your setup according to the information above,
try reducing the speed at which the computer talks to the modem
(if using a high speed modem) until the connection works. If
you have to do this then either you are attempting to drive
your computer or your modem at too high a speed, or you have
other processes running which interfere with the correct
running of your serial communications (as per Serial Chips
above).
If you have finished your live session and log off you may
sometimes find that your phone line is not dropped. This can
result in an unwelcome phone bill! There are a number of
computer/software specific solutions to this problem and some
answers are given in /pub/doc/Support.faq which may have been
included in your installation. One thing to check on your
modem is that the setting that makes the phone line drop when
the computer tells the modem that it has finished, is on. The
computer uses the serial port and drops DTR (Data Terminal
Ready) and the modem spots this and hangs up the line. The
setting often &D2 and you should read the section below which
tells you how to set this. It is definitely &D2 for US
Robotics, SupraFax and Dowty Quattro modems.
If your modem sometimes seems to fail to recognise a ringing
tone, reporting it as BUSY. This can be cured by adding a
comma after the dial number, e.g. "ATDT0813434848,". This
makes the modem pause and ignore the first rings which it
sometimes things is a busy single. Some US Robotics modems can
exhibit this problem.
ATZ is the command that resets the modem. Setting your
initialisation string to ATZA0 etc where A0 is the
initialisation string is very likely to fail. This is because
the modem takes a while to reset and throws away the data being
sent to it in the meantime. Some people beg to differ on this
point. However it is certainly true on US Robotics modems.
Just to confuse matters further there are often some switches
on the modem which you can use to make further settings or to
default to different options. These are referred to as DIP
switches. Mostly, the advice contained in this document,
refers to modems that have not had their switches tampered
with. If you have the manual for your modem (and I hope you
have!) then that will probably tell you what the default
factory switch settings were. Make a careful note of the
current settings and then change back to the factory defaults.
If you already use your modem with other packages, make sure
they still work. These DIP switches must be set to ensure that
the reset command ATZ resets the modem to the stored values.
On some modems it is possible to make ATZ restore to factory
settings which rather defeats the object of configuring it!
Some modems have ATY commands instead of DIP switches and so it
is important that the correct ATY command has been used.
Fortunately, the default will ok if no ATY command has been
issued.
If you are getting a no response from the modem before dialling
(eg. The dialler in KA9Q reporting "INPUT LINE WAIT 3000 OK")
then that means that either your modem is not connected
properly (check the cables, or for internal modems, check
jumper settings, and check software configuration to check that
the dialer is trying to talk to the modem on the correct port),
or your modem is not configured for verbal result codes.
Normally the command to accomplish this is ATV1 .
There is a section below which specifically refers to problems
that may be encountered by PC users.
10. Software and Other Factors
===============================
By configuring your software correctly you can make significant
improvements to an under performing communications connection.
Things to check for include badly fragmented disks (run a disk
de-fragmenter such as Norton's Speed Disk), no disk cache, no
or insufficient buffering inside the software and unnecessary
checking protocols or indexing taking place. Refer to your
software's instructions for details on these.
11. Help for Specific Computers
================================
Some extra comments for some operating systems which may be of use
follows.
11.0. IBM PC Compatibles running DOS
========================================
In addition to the above info there is some specific advice
below for those of you running DOS.
Some modems send back "OK" when sent ATZ (the reset command)
even though they are not ready. This means that the dialer
program will try to ring out even though the modem is not
ready. The effect is that you will see ATZ on the screen
followed by OK and then the program will not dial. Eventually
it will time out. To avoid this, send AT instead of ATZ in the
modem initialisation string.
Extended memory drivers can interfere with the correct
operation of your serial communications. If you suspect this,
rename your CONFIG.SYS and AUTOEXEC.BAT files and then reboot
your computer to see if the connection improves.
If you have a V.32bis 14,400 modem you will probably want to
talk to it at 38,400. Unless you have a suitable serial chip
then you will get errors and, as explained at the start of this
document, this can seriously impact the throughput. When
running NET.EXE you can type asystat at the net> prompt and
information about your serial comms will be printed to the
screen. The interesting parameter is the third one on the
second line, 'hw over'. This shows how many hardware overruns
(characters lost because they weren't fetched from the serial
chip in time) have occurred. These overruns are usually due to
lack of either a buffered UART or hardware handshaking.
As already stated, for maximum performance you will need to
have a buffered chip. For this you will need a 16550A - this
is the number that is written on the chip. The asystat command
will tell you if a 16550 is detected. Unfortunately, even top
manufacturers overlook this area so it is quite likely that
your chip is below par.
If in doubt, open up your computer and locate the serial chip.
If it is not a 16550 then it might need replacing. If you are
handy with a soldering iron you could replace it, but this is
not advisable unless you are really confident. If the chip is
socketed then it can be removed and a 16550 (costing about #16
- we sell them) be put in its place. If not then you could buy
an extra serial card with a 16550 already on it costing from
around #30 to #70 depending on the specification.
Some internal modems use a 16450 with a large buffer (1K) and
this may be enough to stop hardware overruns.
If you are using a standard serial port then the settings
offered for COM1, 2, 3 or 4 in the configuration program in
DIS.EXE will probably be fine. Otherwise you should refer to
your manuals and enter the appropriate IRQ number and I/O base
address.
If you install an extra serial card then be aware that if you
have, for example, a mouse on COM1 then you should not use COM3
for your modem using the default IRQ setting as they share the
same interrupt.
There is another factor that can impede throughput and that is
software overruns. Using the NET.EXE software, at the net>
prompt having just received some news or ftp'd a file, type
asystat and look at the figure before sw over. If this is not
0 then you are getting software overruns. To fix this,
increase the buffer size in the attach line near the top of
autoexec.net:
attach asy 0x3f8 4 ppp sl0 4096 1500 38400
Alter the 4096 in the above to be 8192, 12288 or higher until
the software overruns are cured.
More information on tuning is available in
/pub/doc/ka9q/Tuning.faq.
11.1. OS/2
==============
If intending to run the DIS DOS software in an OS/2 2.x DOS
session you should get a copy of sio126c.exe and install the
communications driver in it before running DIS. sio126c.zip is
available on our ftp server or via our guest download account.
This is because the standard communications drivers do not pass
to DOS the buffering of your 16550A buffered serial chip.
12. Individual Modem Settings
==============================
12.0. Setting up a kind of modem not described below
========================================================
To change the settings of your modem, use a program that can
talk directly to the modem, such as a standard communications
package.
(*) In Windows, you can use Terminal (in the Accessories
Group), setting it for the correct connector (COM Port).
(*) On the Macintosh, you can use ConfigPPP by switching
Terminal Window on, and clicking Open. When you are finished,
switch off Terminal Window again.
Type the reset command, usually ATZ <RETURN>, and see the
response OK. Then continue through the list of settings. You
can type ATI4 <RETURN> or AT&V <RETURN> to see what your
current settings are on a lot of modems. For connecting to
Demon we recommend the following:
Use V.32bis modulation/CCITT protocols rather than HST
Originator mode
Local echo ON
Duplex OFF; receiving system sends duplicate data
All result codes displayed
Display result codes in verbal (not numerical) mode, e.g. OK
not 0
Enable additional error control indicator, e.g. LAPM/V42BIS
Serial port remains at fixed setting
Modem send CD (Carrier Detect) on connection
Terminal sends DTR (Data Terminal Ready)
Data Set Ready (DSR) controlled by the computer
Hardware CTS (Clear to Send) transmit data flow control
Received Data h/ware (RTS) flow controlled by computer
Received Data software flow control disabled (make sure the
modem uses hardware flow control, and switch off
XON/XOFF flow control, also known as software flow
control)
MNP 5 data compression disabled
Variable link speed negotiation
1800Hz UK guard tone on. (Probably AT&G2)
When done, type the command that saves the settings to Non
Volatile Ram (NVRAM) (usually AT&W) so that they areremembered
when the modem is reset.
12.1. Setting Up a US Robotics/Miracom Modem
================================================
To set up your modem, use a standard communications package.
Type ATZ <RETURN> and see the response OK. Then continue to
make the settings. You can type ati4 <RETURN> and ati5 to see
what your current settings are. For connecting to Demon we
recommend the following:
B0 V.32bis modulation rather than HST
C1 Transmitter enabled
E1 Local echo ON
F1 Duplex OFF receiving system sends duplicate data
Q0 Result codes displayed
V1 Display result codes in verbal (not numerical) mode
&A3 Enable additional error control indicator
&B1 Serial port remains at fixed setting
&C1 Modem send CD (Carrier Detect) on connection
&D2 Terminal sends DTR (Data Terminal Ready)
&G2 1800Hz Guard Tone
&H1 Hardware CTS (Clear to Send) transmit data flow control
&I0 Received Data software flow control disabled
&K3 MNP 5 data compression disabled
&N0 Variable link speed negotiation
&R2 Received Data h/ware (RTS) flow controlled by computer
&S1 Data Set Ready (DSR) controlled by the computer
e.g. type AT&K3 <RETURN>. When done type AT&W <RETURN> to save
the settings to Non Volatile Ram (NVRAM) so that they are
remembered when the modem is reset.
Some US Robotics occasionally mistake a System X (and Y?)
ringing tone for a busy tone and hang up just as the Demon end
answers. Sticking a pause on the end of the dialling sequence
stops the modem's response long enough for the Demon end to
start its negotiating sequence. This means that the confusing
System X tone is ignored. If the Demon end is busy you just to
wait a bit longer for the BUSY string, but not as long as the
setting in S7. Add a pause by adding a comma to the end of the
string.
12.2. Apple Express Modem
=============================
Just AT&F then AT&C0 to disable compression
12.3. BT NS 2232 M
======================
(Note this doesn't work reliably with dial, but does work with
TIP or with an outboard Kermit script.)
at &f0 s0=0 x7 m2 &u1 &k0 b0 s30=26 &e5 &r1 &d2 &c1 l3
&f0 - reset to factory default
s0=0 - suppress auto answer
x7 - maximum message generation (for diagnostic purposes)
m2 - speaker always on, so you can hear retrains
&u1 - RTS flow control
&k0 - CTS flow control
b0 - CCITT mode
s30=26 - CTS follows DCD **, plus defaults
&e5 - V.42bis (and LAPM)
&r1 - RTS locked on (??)
&d2 - DTR is Data Terminal Ready
&c1 - CD Normal
l3 - Speaker loud
** the theory is that it would otherwise try to track RTS when
that is used for flow control.
12.4. Dowty
===============
Dowty Quantum 144
To configure this modem for CTS/RTS only (hardware
handshaking):
&k2 Use CTS on transmission
&u2 USE RTS on receive
12.5. Dynalink
==================
Dynalink 1414VE: AT&Q9W1S37=11S48=0M0
&Q9 The modem will attempt V.42bis, fallback to V.42(LAP-
M), then fallback to normal mode.
W1 Reports the error correction protocol and the carrier
speed used.
S37=11 Sets DCE speed (modem to modem) to 14400bps.
S48=0 Disables protocol negotiation. Forces LAPM.
M0 Turns off the speaker. (This thing is loud!).
ATZ or AT&F as the first command as both of these seem to annoy
the modem into false starts.
ACTIVE PROFILE:
B1 E1 L0 M0 N1 Q0 T V1 W0 X4 Y0 &C1 &D1 &G0 &J0 &K3 &Q9 &R0 &S1
&T4 &X0 &Y0
S00:000 S01:000 S02:043 S03:013 S04:010 S05:008 S06:002 S07:050
S08:002
S09:006 S10:014 S11:095 S12:050 S18:000 S25:005 S26:001 S36:007
S37:011
S38:020 S44:003 S46:138 S48:000 S49:008 S50:255
12.6. Gateway
=================
Gateway Telepath modem: AT&K3s48=0s46=138s36=1
The modem works fine at 38400 and most of the time is OK with
14400 carrier. On occasion it works better by setting it down
to 9600 with n0s37=9 added to the init string.
12.7. Global Village
========================
From a user:
The specs for AT commands for a Global Village PowerPort Silver and Gold
modems are as follows:
AT {code} command... action...
\N5 (Set Operating Mode) Set auto-reliable(V.42 LAPM only)
\Q3 (Set Serial Port Flow Control) Enable bidirectionable hardware
flow control
\J0 (BPS Rate Adjust) Disable port rate adjust;
serial port rate independent of
the connection
%C1 (Data Compression) Enable data compression
(V.42bis in LAPM)
<these following could be helpful...>
&W1 (Store Active Profile) Save active configuration as User
Profile 1
&Y1 (Select Stored Profile On Power Up) Recall User Profile 1 on power up
&V1 (View Active Configuration and Stored Profile) View profile 1
12.8. Mistral
=================
For an Amber Logic Mistral FX144 modem.
Use the factory defaults and the following:
&E4 Forces the modem to reject the connection with
the
'NO CARRIER' message if it cannot establish a
V42 link
S31=2 Locks the DTE baud rate to 38400
12.9. Multitech
===================
AT&F
This just resets to factory settings.
From one of our users with a Multitech MT1932ZDXK V32Ter and
fax modem:
AT&F&E2&E7$MB14400X4M0S0=0
The X4 just gives you full result codes - not essential unless
you want to
know exactly what kind of connection you've got.
From a Multitech dealer:
&E4 Hard CTS/RTS
&BA0 Baud rate altering off
&E2 V.42 with no fall back to MNP5
&E15 Compression on
&D2 Hang up the line when DTR is dropped
12.10. Pace Microlin
=======================
AT &K3B0E1F0Q0V1%C2&C1&D2\N3
&K3 - RTS/CTS Handshaking
B0 - CCITT protocols
E1 - Enable Echo
F0 - Negotiate connect speed - may want to use F10 <14.4> if
saving for use with demon only.
Q0 - Enable result codes
V1 - Verbose result codes
%C2 - V42 but no MNP5 compression
&C1 - DCD follows carrier
&D2 - hang up on DTR
\N3 - Autoreliable link - use \N2 to reject links negotiated
without error correction.
AT &W to save as default, or AT &W1 to save in second NVRAM
section for recall with ATZ1 as modem initialisation string.
12.11. Pace Mobifax
======================
For connecting to Demon we recommend the following:
Command What it does
B0 Use V.32bis modulation/CCITT protocols rather than
HST
&C1 Modem send CD (Carrier Detect) on connection
E1 Local echo ON
F0 Variable modem-to-modem speed negotiation
Q0 All result codes displayed
V1 Display result codes in verbal (not numerical) mode,
e.g. OK not 0
X4 Gives full CONNECT string
&D2 Terminal sends DTR (Data Terminal Ready)
&S1 Data Set Ready (DSR) controlled by the computer
&K3 RTS/CTS flow-control
When done, type the command that saves the settings, AT&W, so
that they are remembered when the modem is reset.
12.12. Racal
===============
From a user:
My modem is a model Racal Maxam V 9600 baud, about 2 years
old.I have been told that a Racal connected to a US Robotics
the Racal can detect a higher baud carrier as its own 9600
carrier.When connected you will get lots of 8bit characters
and the modem will then drop the line.This can be solved by
forcing the modem to 9600 and not checking for errors at this
baud rate.
The command string is atn0f8&e0&w0 for a Racal:
n0 - Do not seek the baud rate
f8 - Force baud to 9600
&e0 - No error check
&w0 - Write change
12.13. Rockwell chipset modems
=================================
Rockwell chipsets are used in a variety of modems, namely Supra
and SmartOne.
B0 v32bis modulation
E1 Local echo on
V1 Word response for errors
Q0 Modem sends responses
F1 Duplex off. (Can't find any not to)
&A3
&S1
There is an "undocumented" feature present in the Supra
V.32/V.32bis FAX Modems that can help improve the quality of
FAX and Data transmissions.
The AT\E1 command is not documented in Supra's manuals, but is
present in the Rockwell V.32/V.32bis firmware/chipsets on which
the Supra V.32/V.32bis FAX Modems are based. This command is
documented in the RC96AC and RC144AC Modem Designer's Guide
from Rockwell International.
12.14. SmartOne
==================
(also badged Best Data, CalCom)
&F Restore factory settings
B0 Select CCITT V.22 and V.21 mode
C1 Normal transmit carrier switching
E1 Command character echo enabled
F1 On-line state character echo disabled
Q0 Result code messages sent to machine
V1 Result code messages sent in English word format
&C1 DCD indicates on-line data carrier detected
&D2 Modem disconnects when DTR drops
&G2 1800 Hz Guard Tone
&K3 Enable CTS/RTS flow control
&Q6 Select Asynchronous operation in normal mode
&R0 CTS follows RTS
&S1 DSR turned off while carrier is lost
\G0 Disable Xon/Xoff flow control
For v32bis (14,400 baud) models:
S37=11 Attempt to connect at 14400 bps
12.15. Supra modems
======================
Supra 14.4k fax modems need the ROM revision 1.70B or later but
their ROM revision number is odd. Revision 1.8 or 1.4 are also
apparently OK.
Information providing features
Enable all CONNECT, PROTOCOL & COMPRESSION mesgs: s95=41
loudspeaker control (low volume, on until carrier): l1m1
Modem/PC signals
modems disconnects when DTR drops: &d2
DCD follows line carrier: &c1
Enable hardware flow control: &k3
Speed connection, reject bad lines
new models, only make LAPM Reliable connections: \n4
old models, make AutoReliable connections: \n3
Disable negotiation, make V42 (LAPM) connection: s48=0
connect at highest shared data rate: n1
Compression
new models, V.42bis (BTLZ) Enabled, (but not MNP): %C2
old models, enable data compression (BTLZ or MNP): s41=1
An initialisation string for this would be:
ats95=41 l1m1&d2&c1&k3 \\n4 s48=0 n1 %C2
^note the double '\' is needed if typing this
into some dialer programs
To put this into the modem's memory (NVRAM) type at&w
12.16. Yoriko modems
=======================
Yorikos work OK with a simple AT&F&C1&D2 set-up.
12.17. Zoltrix
=================
These are one of our user's settings for a Zoltrix v32bis
internal fax/modem. He writes:
With X4, W1 and V1, I've managed to configure it very nicely to
redial if the line's are busy after only 5 seconds, report
CONNECT, PROTOCOL CARRIER, and BUSY
The only bit I'm vaguely unsure about is, whether disabling
compression (%c0 on mine), disables v42bis also, as I really
only want to knock out MNP 5. &Q9 I think attempts v42bis,
falls back to LAP-M+v42, then to normal.
An annoying feature is that at&v only digs out probably a
quarter of the settings - the '\' and '%' commands don't
feature; some of them appear extremely useful: %Q for instance
purportedly reports line signal quality, and %L received signal
level, which I reckon might be relevant to one recent spate of
postings, and you can tune up v42bis with others.
S86 stores a connection failure cause code.
OK
at&v
ACTIVE PROFILE:
B0 E1 L0 M0 N1 Q0 T V1 W1 X4 Y0 &C1 &D2 &G0 &J0 &K3 &Q9 &R0 &S1
&T4 &X0 &Y0
S00:000 S01:000 S02:043 S03:013 S04:010 S05:008 S06:002 S07:060
S08:002 S09:006
S10:014 S11:095 S12:050 S18:000 S25:005 S26:001 S36:007 S37:000
S38:020 S44:003
S46:138 S48:007 S49:008 S50:255
Another user writes:
Rom revision (use ATI0 or similar to check) : See below
AT&Q5S48=7S46=138S95=46
Rom revision
------------
I have listed what comes out of ATI0 to ATI4 as ATI0
doesn't make sense!
ATI0 = 14400
ATI1 = 007
ATI2 = OK
ATI3 = V1.410-AP39
ATI4 = a007880284C6002F
bC60000000
r1005111151012004
r3000111170000000
Additional modem string info. (may be of some use)
&Q5 = set error correction mode
causes the modes to try v42bis, then MNP5, then normal
connection
S48=7 = enable V42 negotiation
S46=138 = error correction with compression
S95=46 = display extended result codes
so I can see that i've got error correction
and compression :-)
I also have a line
echo atz > com3:
in my demon.bat file to reset my modem as my fax software
leaves it in a bit of a state :-( Two 'init' lines don't seem
to work (not that I'm bothered!)
Yet another user writes:
This might be helpful if anyone calls using a Zoltrix 28800/
Internal / Fax.
Setup straight from box, using a comms package.
Using factory settings, AT&F,
then alter s7 to = 20 ATS7=20
then alter b1 to b0 ATB0
then alter &q6 to &q5 AT&Q5
optional ATL1 to ATL2 ATL2 - modem volume to hear connect.
and then write these to the stored profiles
AT&W0
AT&W1
Software used:
Windows 3.11 for workgroups
MS-Dos 6.22
DISWIN.EXE from Demon
DIS216C.EXE " "
Cybercom.drv - from ftp.qualcomm.com (can't rem exact loc)
to replace standard comm.drv, supports higher speed 57600+
rather than 19200
In windows system.ini under 386Enh
Com*fifo=1
12.18. Zoom modems
=====================
From one user comes this:
Zoom 14.4X FaxModem Settings
============================
These setting are in use to connect to demon both via KAQ9 and
trumpet winsock (SLIP). The settings enable 14400 bps with V42
error correction and V42bis data compression. In operation I
achieve 2600 cps when obtaining mainly text news. Whilst I am
sure the settings work I do not vouch for the accuracy of my
interpretation of what they mean!!
To reset modem to stored profile:-
ATZ - sets to profile 0
ATZ0 - sets to profile 0
ATZ1 - sets to profile 0
To store current profile:-
AT&W0 - store as profile 0
AT&W1 - store as profile 1
For brevity I have left out setting that have no functional
relevence.
Profile Command comments
E1 ATE1 Command characters echoed
N0 *ATN0 (zero) Disable auto-mode
detection; connection speed specified
by register S37
Q0 ATQ0 (zero) Enable response to computer (DTE)
X3 *ATX3 Monitors busy tones; sends
X2 messages
Y0 ATY0 (zero) Disable long space disconnect
&C0 AT&C0 (zero) Forces RLSD (DCD) on
&D0 AT&D0 (zero) Data terminal ready options
&G2 *AT&G2 Enable 1800Hz guard tone
&J0 *AT&J0 (zero)Disable adjusting DTE speed
&K3 AT&K3 Enable RTS/CTS flow
control. VITAL for slip connections
such as Trumpet winsock
&R1 AT&R1 CTS is always on in
synchronous or drops if required by
flow control in asynchronous
&S1* AT&S1 DSR active after answer
tone detected and inactive after
carrier loss.
&T4 AT&T4 Responds to remote modem
request for digital loopback.
Registers
Set using ATSn=v Sets register n to value v
S37 11 *
All lines with an * are for items than are altered fron the
factory default settings.
We would recommend &d2 otherwise your modem may not hang up the
line when you have finished your call.
From yet another user: The best I've got so far for the Zoom
14.4X is AT&F0W0&C1&D2%C2
&F0 (manufacturer's defaults, so we know where we are)
W0 (limit the messages coming from the modem)
(W1 gives lots of messages from the modem but causes problems
for some people)
&C1&D2 (for hardware flow control)
%C2 (enable V42 bis but not MNP5)
12.19. Zyxel
===============
From one of our users again:
The following "dial_cmd" is for a Zyxel U-1496E+ modem
"ATL2N1X7&G2*E1DT"
L2 --- sets a low (but not inaudible) speaker volume
N1 --- sets a low (but not inaudible) ringing volume
X7 --- sets result code options so that the "connect" message
is, for example, "CONNECT 14400/Arq/V42b"
&G2 -- enables 1800 Hz guard tone
*E1 -- terminate call if error control negotiation fails, ie.
insist on error-control or end call
DT --- dial using DTMF tones
13. Testing
===========
To test out your setup you could try using ping. ping
gate.demon.co.uk whilst logged on directly to gate should
return a speed of about 270ms on a fast link down to 1000ms on
a slow link.
Try using ftp to ftp.demon.co.uk and downloading files from
/pub/test. There are files of varying contents that have also
been compressed in various ways. "empty" files are there so
that you can test the maximum throughput on blank data. "full"
files contain a thorough mix of characters and so little
compression by your modem will be possible. "regular" files are
a mixture - just like this document or a Usenet news message.
Each of these three have been compressed using popular methods
and so you can try working on the compressed files as well if
you like. Try uploading these files to
ftp.demon.co.uk:/incoming to test the link in that direction as
well.
Using a V.32bis modem, the maximum throughput you are likely to
get on a binary file is 1,600 cps. On an ASCII file the
maximum is about 2,800 cps.
14. Finally
============
Please try to sort out your setup by following the above
advice. If you are still stuck then telephone the support line
on 0181-371 1010 during support hours to see if further help
can be offered. Full support line details are available in
/pub/doc/Welcome.txt.