I have a FreePBX (a VM but don't think it matters) server connected to the T1600G L3 switch which is configured on a voice VLAN.
All my Yealink T21s are on the same voice VLAN and everything is and has been working great for 18 months.
I've been trying to configure softphones to enable staff to work remotely over the VPN but have had one-way voice issues. Initially I thought it was the VPN causing it but I spent some time onsite today and found the issue occurs on the internal network as well.
My softphone was on the data VLAN and I got one way audio calling internal extensions on the voice VLAN. In another test I connected a T21 to the data vlan and called a phone on the voice vlan - only had one way voice as well. Connected to the same voice vlan and everything was great. This leads me to think the issue is perhaps with the T1600G routing between VLANS? Or some misconfiguration on the FreePBX server (I have my local subnets listed in Asterisk SIP and have my 10.0.0.0/8 network trusted in the firewall).
The T1600G doesn't have any SIP SLG features and the security features are all disabled so maybe the switch isn't to blame at all. I'm not really sure.
I've run out of ideas and am now considering what other options I have. Any thoughts welcome.

