Grandstream Phones

[cg12510]

I have 3 grandstream phones 2 located at differnet offices and 1 located by a server. The phonesin the offices can call back to the "server" phone, but cannot contact each other direct. any ideas or suggestions why? We are using the free version of the phone system.

Thanks

 

[leejor]

The two phones "located at different offices", are they both at the same location? Do you have STUN enabled on the remote sets? Have you tried changing the "PBX delivers audio" option on the lines. What does the 3CX log show when you attempt a call, and it fails?

 

[cg12510]

Leejor,

When we attempted from one phone to another there was a ringing but no audio on the phone when picked up. After several second the handset would go into a busy signal.

tks