Trouble Shooting Guide - Cortelco 2740 Instruction Manual

No Display or Lamps
No Dial Tone
The LED's are Flashing and
the Display reads "Station
#??"
There is no dial tone on the
handset, but the speakerphone
works.
The Intercom does not work
Or
The telephone does not show
the status of other telephones
Or
There is a delay in getting
dial tone
Or
The Telephone remains on
hold after the call is picked
up at another station.
Crosstalk or other
interference
The line LED flashes when a
call comes in, but the
telephone does not ring.
The telephone does not
operate during a power
outage
The battery icon stays lit in
display
You cannot join a telephone
call in progress.
The telephone line status
indicators stay lit, even
though the line is not in use.
Appendix D

Trouble Shooting Guide

Make sure that the Power Transformer is plugged into an electric socket not controlled by a
wall switch
Check all line connections. If possible check your jack wiring by testing a non-system
telephone at the jack in question. If a standard telephone does not work, then the local
telephone company lines or your house wiring may be causing the problem
Press soft key "Change" to assign this telephone a station number.
Replace the handset from another 2750 telephone. If this solves the problem, then contact
Technical Support for assistance.
The problem may be with your installation. Make sure that the lines are installed correctly
and that line 1 is common on all system telephones.
The cause of this problem may be from outside interference. Disconnect line one at the
cable terminal. If this solves the problem, then the interference is coming from the
telephone company.
This problem may also be caused by DSL Microfilters. Never connect a line that has a
DSL Circuit on Line 1.
The problem may be caused by one defective telephone. Disconnect one instrument at a
time to determine if a particular telephone is causing the problem.
The most common cause of crosstalk is the use of flat cable. Be sure to use supplied line
cords. You must use twisted-pair line cords.
Make sure that the Ringer is on and that "Do Not Disturb" is off.
Make sure that fresh AAA batteries are installed in base.
Make sure that fresh AAA batteries are installed in base.
The Call Privacy feature prevents another 2740 or 2750 from interrupting a call in
progress. If you don't want Call Privacy in your system, then go into system programming
on station 01 and turn it off.
If this line is not connected, then program it as unconnected. If this line is connected and
you have dial tone, then adjust loop voltage detector setting.
34 2740 User Manual Version 1.11