Contact US

Log In

Come Join Us!

Are you a
Computer / IT professional?
Join Tek-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Tek-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

No Sound Twinning with Peerless SIP Trunks

No Sound Twinning with Peerless SIP Trunks

No Sound Twinning with Peerless SIP Trunks

IP Office Desk Phone 9608. If Relevant
Have setup Peerless SIP trunks in accordance to Avaya Doc.
Everything working great. Routing, Inbound, Outbound.
But when twinning I am getting no audio.
If I interrupt the call I do get audio on Desk Phone. Both ways.
I can then twin/transfer to cell phone and get audio both ways. But on initial twinning no audio either direction.

I've tried tweaking Allow Direct Media Path Settings as well as playing with Mobile Delay and Mobile Answer Guard timers. Hoping maybe something there. To no avail.
I do notice even if I set to delay twin in System Status I see system seize second trunk even before it starts to dial. Not sure if relevant either but something noticed.
Thanks in advance for any assistance.

RE: No Sound Twinning with Peerless SIP Trunks

This is a classic RTP Keepalives problem, the SIP works fine but you get this when you use mobile twinning to SIP, I had the same problem at one of my customers. It is set in the VOIP tab of the LAN interface you use for the SIP trunk.

Set PERIODIC TIMEOUT to (try different settings I started at 10 seconds and worked my way down)

“Some humans would do anything to see if it was possible to do it.
If you put a large switch in some cave somewhere, with a sign on it saying 'End-of-the-World Switch. PLEASE DO NOT TOUCH'.
The paint wouldn't even have time to dry.”

Terry Pratchet

RE: No Sound Twinning with Peerless SIP Trunks

Thanks for reply Ekster.
It was set for RTP-RTCP Timeout 30 and Enabled.
Changed to just RTP. Played with timeout from 10 down to 1.
Unfortunately still had same issue. No sound if doing twinning.

Really appreciate you taking time to reply.

RE: No Sound Twinning with Peerless SIP Trunks


I got the same issue.
Provider didn't like to reroute voice to an other destination.
What I found is using different codecs for incomming and outgoing communications.
Then, the IP Office has to stay in the path.

Ask provider to accept G711 A-law AND U-Law codecs (G729 is ok, but, quality... )

Codec order in system :

Codec order in Sip line :

Solved the issue for me.

RE: No Sound Twinning with Peerless SIP Trunks

So got this resolved.
Used variation of what MrFoof recommended. Thank you sir.

Carrier couldn't understand my request so took variant path.
Took Original SIP line. Copied and Pasted into Second SIP line.
Then went into Original SIP line. Set for Inbound Only. Set Codec to G.711U
Went into Second SIP Line. Set for Outbound Only. Set Codec to G.729 (Carrier doesn't support G711A)
So calls come into Original SIP Line as G.711U but then twin out on Second SIP line as G.729. Voila. Have Audio.

And so you know. Having them both at G.711U did not provide audio. Had to have different Codecs.

So far so good!!! I'm going to go have a bourbon.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Tek-Tips Forums free from inappropriate posts.
The Tek-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Tek-Tips forums is a member-only feature.

Click Here to join Tek-Tips and talk with other members! Already a Member? Login

Close Box

Join Tek-Tips® Today!

Join your peers on the Internet's largest technical computer professional community.
It's easy to join and it's free.

Here's Why Members Love Tek-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close