I have same issue with GXP2130. I tested a little bit further and find out that partially FreePBX must do worst than it is already.
With Page Pro multicast isn’t working (with GXP2130) either announcement nor live talk afterwards. If I use an extension custom entry like
exten => 881,1,Set(ANNOUNCEMENT=custom/soundfile)
exten => 881,n,ANSWER()
exten => 881,n,dial(MulticastRTP/basic/224.100.100.100:5555,10,gFA(${ANNOUNCEMENT}))
the live stream after announcement works. Yealink T23 has same issue. The announcement isn’t working either. Concerning announcement I got feedback from Yealink. This is missing timing info in RTP stream, what is an Asterisk issue. Some phones like Snom or Yealink T42 have other hardware which can handle the missing time.
FreePBX uses confBridge instead of “dial”. confBridge seems to have same timing issue while dial delivers it correctly.
Rds, Enrica