We were experiencing an oddity with our shiny-new SX20 wherein 20 minutes into a VC, it would drop the call. This behavior appears to have stopped when the local folks found and deleted the 20-minute timeout on the HDTV they're using as a primary display. Will the SX20 drop a call if it detects that the display on the HDMI port has powered off or otherwise gone away?
Normally disconnecting the display should not affect the call. What is the software version you're running on the SX20. What kind of call is it ? H323 or SIP? Within same netowrk or outside network? Can you try an IP to IP call which should isolate the issue to be an endpoint issue or not?
Please let us know and we will assist you further.
Sounds more like a network related issue but if it's related to the timeout on the HDTV for sure, then call drops might be due to the CEC support on SX20. But the real question is why the main display goes in standby mode while the system is in a call? Is it an one way video call?
Just to isolate Display,
1. Disconnect display and make call.
2. Change standby timer to minimum like 2 minute and then make test call and see is it getting disconnected ?