NEC XN120 telephone system known problems

Applies to

This article applies to the following products.

Noise and crackling on many or all calls both internal and external from all telephones

Symptoms

There is a loud crackling or buzzing sound on all calls both internal and external. If you have a door phone connected to the XN120, calls from that are also very noisy. The problem affects all telephones connected to the system equally. The sound is loud enough to make conversation impossible. The problem started with a little bit of crackling that was not too bad at first but got worse over a period of a few days or maybe a week or two. Eventually you cannot make or receive any calls at all. If the power is turned off and back on, the system might fail to start up.

Cause

One or more components has failed in the power supply or control unit.

Repair

We can normally repair by either replacing the power supply or the control unit, which includes a new power supply.

Noise and crackling on many or all calls both internal and external from one telephone

Symptoms

On one telephone, or only a small number of telephones, calls are noisy and crackling. Sometimes you can hear the noise but the person at the other end tells you the call is perfectly OK, sometimes the other way around, with the call sounding OK to you but the person at the other end tells you that the call is noisy. The other phones connected to your system work without a problem.

Cause

The curly cable between the base of the phone and the handset has become damaged. Usually this happens at the point where the cable goes into the handset. To test, make a call, bend and move the cable around at the point where it goes into the handset. If moving the cable around makes an obvious difference to the noise, the problem is the cable.

Repair

Replace the cable. On most types of telephone, the cable is plugged into the base of the phone and the handset so it is easy to replace. We can supply replacement cables.

Text reversed on the display of an NEC Vision display telephone

Symptoms

The text on the display is backwards, in particular the extension name is backwards.

Repair

Unplug the telephone, plug it back in, and wait for it to start up. The text should be the right way around.

None of the buttons on the telephone work

Symptoms

  • Nothing happens when any of the buttons are pressed.
  • The telephone might or might not work for incoming calls, but you will not be able to make any outgoing calls.

Cause

One or more of the buttons is stuck down. Buttons can become stuck if dirt or grit gets trapped between the button and the case.

Repair

Find the stuck button by pressing each button in turn and feeling for the button press. Clean any stuck buttons you find and the case around them. It might help to unclip and remove the clear plastic cover from the front of the telephone and wash it in warm soapy water. Make sure it is completely dry before putting it back. Once the telephone is clean and all the buttons are able to move freely, plug it back in to test. If the problem persists despite cleaning, please contact us for help.

One or more NEC Vision display telephones not working

Symptoms

The display of one or more NEC Vision phones looks similar to the following. Depending on the hardware version, the phone(s) might also be ticking.

SUN 0 0 00AM
-------(1)------

Cause

The telephone or telephone system is starting up. This is normal for the NEC Vision display telephones when they are plugged in or the system is switched on. This condition can persist for about 3 to 5 minutes after the system has been switched on, after which the telephone should start up. If it does not, there are a number of possible causes. If the problem affects only one telephone, the telephone might be faulty or there might be a wiring problem to the telephone socket. If the problem affects all the telephones, there might be a problem with the telephone system control box.

Repair

If only 1 telephone shows the problem and the other are working, try unplugging it and plugging it back in, then wait a few seconds while it starts up. If the problem persists, try a known working telephone in the same socket. If that telephone works correctly, the problem is with the telephone. If it doesn't work, there might be a wiring or system fault. Please contact us for help.

If all the telephones, or at least the first 8 if you have more than 8 telephones, have this problem, there is likely to be a fault with the XN120 control unit. Check the amber light in the centre of the control unit. It should be flashing slowly. If it is on but not flashing, there might be a fault with the control unit. Try turning the power off and back on, wait 5 minutes and see if the problem is resolved. If not, please contact us for help.