Connection between the central office and the PBX:
CAUSE
CO line is connected to the T2/T1.
SOLUTION
Reconnect the CO line to
the T1/R1 or T2/R2 of the
telephone jack using 2-
conductor wiring.
T2
R1
T1
R2
CO line PBX
CO line is connected to the T2/R1.
PBX
CO line
T2
R1
T1
R2
No
Can you dial
out on a CO
line?
No
Can you dial
an extension?
Connection between the PBX and an SL
T that is polarity-sensitive:
PBX
CAUSE
The "T" is connected to the "R".
SOLUTION
T
R
T
R
Extension
Reverse the connections of
the T/R.
Yes
Connection between the PBX and an SLT:
CAUSE SOLUTION
If a telephone equipped
with an A-A1 relay is
connected to the PBX, set
the A-A1 relay switch of the
telephone to "OFF".
Use the correct cord (the
inner 2 wires are for T/R).
PBX
The T/R is connected to the D1/D2.
T
R
T
R
Extension