Common ISDN faults
ISDN lines have many advantages but are dependant on power supply, hence if you have a power outage your ISDN Lines will stop working. It may be a good idea to connect the ISDN NT units to a UPS or battery back up supply. Needless to say, you would need to ensure that your PABX has power as well. Many businesses prefer to have a PSTN line as a backup.
Common symptoms:
Cannot recieve calls nor dial out: Callers calling in are getting busy tone and there is no dial tone on the phones.
Tip: This could be because either the PABX, the NTU or both do not have power supply. If you cannot dial internal extensions, you need to check to see if the PABX is working.
What to do: Check to see if power supply is ON. A power reset helps in most cases but if does not resolve the issue, you may want to call your PABX vendor for advice in the first instance.
Incoming calls get busy tone but dialing out is OK: Callers cannot get through but you can dial out.
Tip: This could be because the NT Unit is not in sync with the ISDN device (PABX).
What to do: Check the NTU to see if it is in sync with the PABX. Switch Off the NTU and wait 30 seconds before switching it ON again. This should help resync teh NTU and PABX, however if still out of sync, The PABX may need to be reset as well. You may want to call your PABX vendor for advice. You can also contact your service provider to have a test done on the line to see if the circuit is OK.
A specific DDI is not working: Callers can call other DDI numbers to the same business but not a specific DDI.
Tip: This could be because either the DDI has not been programmed correctly in the PABX, or more likely the extension phone assigned to the DDI is set to Do Not Disturb or is faulty.
What to do: Check extension phone and confirm DND is not set. If the phone itself does not work, replace with another phone and see if this works. Remember, if you set DND on an extension, replacing the phone will not take off the DND but instead, it needs to be deactivated.
None of the DDI's work but Main line works: Callers can call the Pilot number but cannot call any of the DDI's.
Tip: This has to do with the DDI configuration and way the DDI's are programmed in the PABX.
What to do: Call your provider to confirm you have your DDI numbers and these have not been disconnected. Also confirm the number of 'digits forward' and if the ISDN BRI is set to Point to Point or Point to Multipoint. Next call your PABX vendor and advice them of the issue and give them the config details so they can match the settings in the PABX. The Pabx technician will be able to advice if config changes are required at the service providers end.
Common symptoms:
Cannot recieve calls nor dial out: Callers calling in are getting busy tone and there is no dial tone on the phones.
Tip: This could be because either the PABX, the NTU or both do not have power supply. If you cannot dial internal extensions, you need to check to see if the PABX is working.
What to do: Check to see if power supply is ON. A power reset helps in most cases but if does not resolve the issue, you may want to call your PABX vendor for advice in the first instance.
Incoming calls get busy tone but dialing out is OK: Callers cannot get through but you can dial out.
Tip: This could be because the NT Unit is not in sync with the ISDN device (PABX).
What to do: Check the NTU to see if it is in sync with the PABX. Switch Off the NTU and wait 30 seconds before switching it ON again. This should help resync teh NTU and PABX, however if still out of sync, The PABX may need to be reset as well. You may want to call your PABX vendor for advice. You can also contact your service provider to have a test done on the line to see if the circuit is OK.
A specific DDI is not working: Callers can call other DDI numbers to the same business but not a specific DDI.
Tip: This could be because either the DDI has not been programmed correctly in the PABX, or more likely the extension phone assigned to the DDI is set to Do Not Disturb or is faulty.
What to do: Check extension phone and confirm DND is not set. If the phone itself does not work, replace with another phone and see if this works. Remember, if you set DND on an extension, replacing the phone will not take off the DND but instead, it needs to be deactivated.
None of the DDI's work but Main line works: Callers can call the Pilot number but cannot call any of the DDI's.
Tip: This has to do with the DDI configuration and way the DDI's are programmed in the PABX.
What to do: Call your provider to confirm you have your DDI numbers and these have not been disconnected. Also confirm the number of 'digits forward' and if the ISDN BRI is set to Point to Point or Point to Multipoint. Next call your PABX vendor and advice them of the issue and give them the config details so they can match the settings in the PABX. The Pabx technician will be able to advice if config changes are required at the service providers end.