SV9100 - Strange no-speech issue on external calls to certain extensions

[bigdave1980]

Hello everyone,

Customer has a SV9100 CP20 system with SIP trunks and DT900 IP handsets. They have a DDI pointed at a VRS message in the DDI routing table. VRS is functioning as an AA, in that it gives options to choose from. Caller to the DDI chooses for example option 2. AA single digit option 2 points at a virtual extension. This virtual extension is forwarded to department group 2. Department group 2 contains 2 extensions. This has all been working fine for over a year, I am aware that it's a bit of a strange setup but it has been working fine and cannot easily be changed now, and I didn't build the system myself.

A few days ago they reported that the phones mentioned above stopped ringing audibly when a call comes in to option 2. They still light up but when answered there is no speech in either direction. I have done some testing and this is what I've found:

If called internally, directly, the handsets ring audibly as normal and can be answered with speech in both directions.
If called internally via the virtual extension (forwarded to the department group) the handsets ring audibly and can be answered with speech in both directions.
If option 2 at the AA is selected, which also points at the same virtual extension, they don't ring audibly and there is no speech when answered.
If an alternative test DDI is pointed directly at either of the 2 extensions, they don't ring audibly and there is no speech when answered.
If an alternative test DDI is pointed at the virtual extension, they don't ring audibly and there is no speech when answered.
If a test DDI is pointed at another internal VOIP extension, it rings audibly and there is speech as normal when answered.
If they unplug one of the problem phones and move it to a location where there is a working phone, swap them out, test calls to the DDI do not ring audibly and when answered there is no speech in either direction.

I've tried a system reboot, I've tried a SIP router reboot, I've tried rebooting the handsets, it's still the same.

This seems like some kind of network issue to me but does anybody else have any suggestions please as this one's driving me up the wall.

Thanks,

Dave

 

[CoralTech]

Call the voicemail and see if you got voice. Sounds like a DSP issue. Check to see someone isn't on your IPLE card IP address.

 

[bigdave1980]

CoralTech Thanks, I'll take a look at that in the morning. I was thinking somewhere along the lines of a DSP issue too. I couldn't understand how an internal call could ring the phone and be answered with speech in both directions, but any kind of external call doesn't ring the phone properly (no sound) and there's no speech in either direction once answered.

I will update here again tomorrow.

Thanks

 

[bigdave1980]

After lots of testing, this turned out to be a local network issue. The customer's IT company were advised to reboot network switches which they did, restoring full service to the affected phones.