[Asterisk-Users] Fun new problem with Aastra 390 ADSI phones

[asterisk at billheckel.com]

I seem to have discovered a problem with the Aastra 390 phones or possibly with the channel banks I 
am using, Carrier Access Access bank 1s.

Users were complaining that when they answered an inbound call, sometimes the phone would buzz and 
go dead on them.

I tried playing with it a bit to see what might cause it and found that if a user answers during the 
ring, the phone goes haywire, buzzes, screen flashes, gets ugly.  The calling party hears an answer, 
ringing stops but no connection.  After a time or 2, the phone won't work at all on inbound calls 
and has to be replaced.

How quickly after off hook should an FXO device drop ring voltage to normal line voltage?  It might 
possibly be this but I really don't think these CAC banks would be that far out of spec.

Has anybody else seen this or do I have a bad batch?

Bill