Missing SDP from Grandstream WP825

#1

A call to the grandstream wp825 is dismissed > after 180 ringing there was no SDP from the grandstream, and the pbx than cancel the call.

grafik

#2

180 do not generate sdp ?
183 generate sdp

#3

Sure - but after the 180 ringing, an SDP should be sent from the grandstream, right?

#4

No, 180 generate at caller side. GS will not open sdp.

#5

The SDP will be generated when the call is answered (200OK) or, as Marcin indicated, if the UCM starts with a session progress (183) which is unlikely given that the call is destined for a device on the same network and presumably, the UCM knows if the device is registered.