No voice of called during a call from a queue

General
1

Dear
I have created 2 queues and i have add 3 member (2 for one queue and 1 one for other).
I have created the follow extension:
exten =>106,1,Queue(tecnico)
If an internal sip member call 106 the member of tecnico received the call and is all ok)
The probem is when the call arrive from external.
When a person call my number voip and after press 2 to enter in tecnico queue the telephone ring but the caller can’t hear the voice of called but called can hear the voice of caller.
I can’t understand why with internal call the queue work normally (called hear the called and called hear the caller) but from external not.
Help me please.
Thank you

2

Is this specific to Queue? It sounds like misconfigured NAT, but this would also affect Dial.

3

extension.conf

exten =>104,1,Answer()
same =>n,Set(CHANNEL(language)=it)
same =>n(voceregistrata),Background(voceregistrata)

exten =>1,1,Dial(SIP/EMANUELE&SIP/PIETRO,20,tTm)
same =>n,Dial(SIP/MARCO,10,tTm)
same =>n,Playback(nbdy-avail-to-take-call)
in this way work

exten =>1,1,Queue(tecnico)

In this way i can hear the voice of caller but caller can’t hear my voice

exten => 106,1,Queue(tecnico) --> in this way i make an internal call and caller and called can communicate.

4

I have found the problem; is my sip phone linksys.
Is ip phone spa942.
I have try with a normal phone and it is all ok.
Do you know which setting is need to change on my sip phone?