Bcm50 to BCM400/200 no speech path on handsets

[ccnet]

I have 2 BCM400's, 1 200 and a 50 all vpn connected with no problems between 400's and 200 but have one way speech path between 50's handsets and any other of the systems. I get ringing both ways but on picking up handsets just voice one way into 50 no voice from it. Although can get calls forwarded from and to the 50 and also use voicemail remotely so it's just calls to and from handsets that are affected.
All systems ping each other and the ip.phones on the 50 are manually configured.......any hints greatly appreciated

 

[biv343]

Codec or payload size mismatch would be my first guess. Make sure that your codecs are configured in the same order on all the systems, and also that the payload sizes are configured appropriately. G.711 defaults to a 20ms payload on the BCM 50 if I'm not mistaken.

 

[ccnet]

Have checked and all are set the same

 

[ford53]

Check your Router or firewall for blocked ports.