Forum Discussion

Brass Contributor

Oct 23, 2019

Solved

Cannot resume/end pstn call that has been placed on hold?

Hi All, A weird issue we've had when doing some testing on a tenant. They have direct routing in place with an Audiocodes vSBC and BT SIP trunks. If we place a call in from a mobile to a ...

Alex_Dunlop
Feb 12, 2020
Gfyrlw

I managed to resolve this issue by working with the SIP carrier, they hadn't approved Teams on their trunks so we had to start from scratch and now have a working config.

On our Audiocodes SBC I have the SIP Trunk IP profile set a specific way for hold and retrieve, see attached screenshot.

There is still a time delay when resuming a call but this is an MS issue that they are aware of.

Alex_Dunlop

Brass Contributor

Oct 25, 2019

Lee Ford Here's an example call and syslog from the audiocodes. It seems like when the client places the call on hold its almost as though the original call then ends, (i see a bye message) then when you try to retrieve that call off hold there is a 481 Call/Transaction Doesn't exist message.

heldcallfail.zip41 KB

Lee Ford

MVP

Oct 25, 2019

So the original call looks to be put on hold to transfer to a 3rd party? I can see the REFER from Teams which is accepted, Teams then sends a "user initiated" BYE message, before the INVITE to the 3rd party arrives. What is strange is the 3rd party call to the SIP provider is where the 481 occurs, not with Teams - which is strange.

Just to confirm, you have added the "Teams REFER" rules in to your SBC IP 2 IP routing rules?

Alex_Dunlop
Brass Contributor
Oct 25, 2019
Yep the REFER rule is in place.

What's odd is when you place the call on hold the client seems to briefly flick as if its gone to a new call. Which is maybe where that BYE message is coming from?
- Alex_Dunlop
  Brass Contributor
  Oct 28, 2019
  Further to this, after much testing and tweaking i've now managed to get a little further. After changing some options in the SIP trunk IP Profile i've now got hold and retrieve working, but i don't get music on hold now.
  
  I'm pretty sure this is a SIP trunk issue, i've reached out to the carrier to see if they have any ideas.
  
  I've put a screenshot down below of the IP profile tweaks i've made.
  
  Alex
  - Gfyrlw
    Iron Contributor
    Feb 11, 2020
    Alex_Dunlop
    Do you have any updates?
    After working with MS for 4 months on this issue the L2 telsl me that they are aware of the issue and it is on the roadmap. Hard to tell if the tech is providing the truth or BS.
    We are definitely frustrated with a Beta product being released to their users and having us debug their software for them. Have tested a different HPBX Product and will probably migrate by end of month.
    Rob