AT&T 7400B Plus User Manual page 124

CHAPTER 5: TROUBLESHOOTING
Page 5-2
Symptom
All LEDs are off.
POWER/TEST and
DATA LEDs flash
together.
Characters typed on
keyboard are not
displayed on the screen
of the terminal device.
Problem
Power is off.
The 7400B Plus has lost
communications with
the PBX.
If the SD LED does not
flash when keys on the
terminal are pressed,
the EIA-232-D cable is
not connected or not
properly wired.
If the SD LED flashes
but the RD LED does
not flash, the command
echo option is turned
off.
The SD and RD LEDs
flash, but certain EIA
signal leads are turned
off.
DEFINITY Communications System
7400B Plus Data Module
Solution
Check that the AC outlet is
working. Check that the power
supply unit is connected to the
7400B Plus and to the AC outlet.
Check that the D8W cord is
connected between the LINE
connector of the 7400B Plus and
a PBX wall jack. Note also that
the line from the PBX must be
properly administered for the
7400B Plus.
Connect or replace the EIA-232-
D cable between the 7400B Plus
and the local terminal device.
Press ( ) to start a new
Enter
command line, and then type
ate1 ( )
Enter
to turn on the command echo.
Press ( ) to start a new
Enter
command line, and then type
at&s0&c0 (
Enter
to ensure that the appropriate
EIA signal leads are turned on.
User´s Guide
)