[E63] One-way audio after assisted transfer with Asterisk 1.6

[cmammoli]

Hi, we have ~ 100 Nokia E63 in our company used as SIP extensions.
Firmware version is 500.21.009

The problem we are experiencing is the following:

A=caller (internal or external)
B=receptionist
C=Nokia phone

A calls B
B puts A on hold
B calls C
B transfers A to C
B hangs up

Now A can hear C BUT C can't hear A
If C presses any key on the keypad, the call starts to work 2-way

No nat is involved in our setup: all phones and PBX on the same subnet

[forceps]

What are you using as the sip server here?
It sounds like it could be a re-invite problem to me.

I don't know if your sip server could handle it, but my easy solution would be to disable re-invite on calls to the nokia devices and force the rtp path through the server at all times.
This would work in very simple cases with low loads, but if you have heavy loads, depending on the sip server deployed, it may not have the ability to keep up (cpu/bandwidth).