Noisy SIP line

[Simons]

Afternoon everyone.

I've had a complaint from one of our users who is experiencing a static noise on the line when making some calls.

We have Mitel 5340's in the office and have a new HP PoE switch. There is only 3 phones in the office. She has also experienced this issue at another office which has a different SIP provider.

Any idea's?

Thanks
Simon

[dilkie]

same problem with handset and hands-free, speaker phone?

sounds like a h/w problem with her set.

[Simons]

Hi Dilkie

The user uses a different handset at a different site so it can't be that!

Thanks

[dilkie]

sorry, I read it differently, that the same phone connected to different sip providers had a noise issue.

beats me... I have seen noisy sip trunks on rare occasions, all due to issues at the provider's media gateway where it interfaces with the PSTN. But hanging up and making a new call always resolved.

[Simons]

Yeah the user does hang up the call (because of this noise) and then makes another call and all is fine.

Just want to know why it's doing it, maybe i could put QOS on the line???

[dilkie]

QoS won't help.

Static/noise is an analog problem, not a digital one. If it was a network problem, you'd be experiencing audio dropouts or studdering or glitches but not "noise".

There are only two places where the audio is analog, in the set and at the pstn gateway.

And to be clear, when you say "noise", you can still hear the other person but it's a staticy call, right? Not a call that is completely static (that's usually the result of mismatched encryption and decryption keys).

[Simons]

Ok i won't use QOS!

The users exact words were..."at odd times when using the phones either when we dial out or when others dial in – there is suddenly a huge static noise on the line and you have to hang up!"

I know there is no easy answer for this so am happy to try anything!

Thanks for your reply again

[dilkie]

are these phones connected to a 3300?

if the "static" starts at the beginning of the call and doesn't end, it could very well be a decryption issue. You could try turning off rtp decryption on the 3300 to see if that helps (sorry, I don't know the command for that).

Are you using an MBG to interface with the sip provider?

[Simons]

Yes they are teleworker handsets connected to a 3300 via MBG

[v2win]

Is it possible its at the other end maybe the user is calling the same number for both sites?