 -=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-
     LINE SIGNALS IN CCITT SYSTEMS
 -=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-

   You will be given an entry followed by 4 pieces of
information on that entry.  The titles for those 4 pieces of
information are: Direction, CCITT #3 (1VF), CCITT #4 (2VF), and
CCITT #5 (2VF).  The individual pieces of information will be,
for the most part, abbreviated 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,xSxSxSx,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-200MS)
CLEAR FORWARD (DISCONNECT):  -->,XXSXX,PXX,X+Y
DISCONNECT ACKNOWLEDGE:  <--,XXSXX,PYY,X+Y

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
* = Combination #15 of Address Code

