ISDN2 / ISDN30 Digital Lines

Faults on ISDN2 / ISDN30 channels can often be issues relating to customer equipment (the telephone system for example).  

The checks below should help ascertain where the fault lies but if you are still unsure it may be worth contacting your telephone system maintainer who can often dial into the system remotely to check the system status.

You can also ask yourself the following questions:

1)      Does the fault affect all extensions?  If not, this is an equipment or wiring fault and not the line itself.  This is because the circuit is tied to the main telephone number therefore, if this was at fault all extensions would be affected.

2)      What is the status of the lights on the ISDN box?  There will be a number of ISDN boxes on site with a series of lights on the top of them (often kept in the server room).  The status of these lights can help to diagnose whether this is a fault on the network (the line) or not.

  • If the green power light is illuminated this suggests that you are connected to the network and that the line is live.

  • If the green power light is flashing the power is likely to be on standby and your telephone system may need rebooting.

  • If the green power light is out then you may have a fault with the line.

  • Similarly if the red light is lit this too could indicate a line fault.