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LINE SIGNALS IN CCITT SYSTEMS
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You will be given an entry followed
by 4 pieces of information on that en-
try. The titles for those 4 pieces of
information are: Direction, CCITT #3
(1VF), CCITT #4 (2VF), and CCITT #5 (2
VF). The individual pieces of infor-
mation will be, for the most part, ab-
breviated to the use of symbols, the
symbols table will follow the entries
at the end of this section.
SEIZE TERMINAL: -->,X,PX,X
SEIZE TRANSIT: -->,N/A,PY,N/A
START PULSING-TERMINAL: <--,X,X,Y
START PULSING-TRANSIT: <--,N/A,Y,N/A
END OF PULSING (ST)*: -->,250MS,xSxSxS
x,1500+1700HZ
BUSY: <--,XX,PX,Y
ACKNOWLEDGE: -->,N/A,N/A,X
ANSWER: <--,XSX,PY,X
CLEAR BACK (ON HOOK): <--,XX,PX,Y
RING FORWARD: -->,XSX,PYY,Y(850+OR-200
MS)
CLEAR FORWARD (DISCONNECT): -->,XXSXX,
PXX,X+Y
DISCONNECT ACKNOWLEDGE: <--,XXSXX,PYY,
X+
SYMBOL TABLE
X = 2280+OR-6HZ,120+OR-30MS
XX = 2280+OR-6HZ,600+OR-120MS
S=100+OR-20MS SILENCE
<-- OR --> = DIRECTION
Those were for CCITT #3 (1VF) (Second
item after each signal)
X = 2040+OR-6HZ,100+OR-20MS
Y = 2400+OR-6HZ,100+OR-20MS
XX = 350+OR-70MS
YY = 350+OR-70MS
S = 35+OR-7MS;x:2040HZ,35MS
P = (2040HZ,2400HZ),150+30MS
Those were for CCITT #4 (2VF)
X = 2400+OR-6HZ
Y = 2600+OR-6HZ
Those were for CCITT #5 (2VF)
N/A = Not Applicable