GrandStream DP750 Call Quality Issue

[Joshua Reed]

Good afternoon Support.

 

I am having issues with Grandstream DP750 cordless base stations.  The only sound that I can hear out of the handset is a garbled echo of what was said into it.  The other side hears just fine.    I can register this device with our local PBX, and to another cloud SIP service and it works fine.  I have tried hooking up a different model IP phone to the same cable and everything functioned properly. 

 

One odd thing that I noticed with a packet capture Is the DP750 is doing a crypto key exchange with your server.  I am not seeing this happen with this phone connecting to other servers, and I am not seeing it with other model IP phones connecting to your server.  

The firmware is 1.0.11.2

Thank you
Josh