Issue with 3CX External Extensions (One Way Audio)

[jzollo]

Hello,

My company has a client who is using the 3CX Phone System and for some reason whenever someone with an external extension makes a call, the audio is only going one way. For example, if I do an external extension to external extension call, the person I call can hear me, but I cannot hear them.

I can confirm that ports 9000-9049 are forwarded to the server with 3CX installed.
I can also confirm that the STUN server is listed as stun3.3cx.com.

I would appreciate any insight into this problem. Thank you in advance!

 

[leejor]

For example, if I do an external extension to external extension call, the person I call can hear me, but I cannot hear them.

I'm going to assume that you are making this call from the remote extension.

This could be a number of things, but is quite a common issue. You mentioned STUN, is it being used on the set/ATA at the remote end (it should be), or did you mean you had STUN enabled at the 3CX end?

I'm going to assume that the remote set is behind a router. Are there any other SIP devices at the same location that may be "intercepting" ports" (port conflict).

It could be a router compatibility issue at the remote end. Some routers do not play well with SIP, some have built in ATA's that require, some, "adjustments"

What does the registration for the set look like in the 3CX log? Does it show the public IP (remote end) and port (usually 5060) ?