I have zero experience with Cisco phones, but I know that other ATAs have this 
issue as well. Basically the CPU doesn't have enough power to run 2 calls at 
the same time using g729 compression. Or with some ATAs that have 2 lines, only 
one at a time can run a 7729 calls, but not both simultaneously.

Liviu
  ----- Original Message ----- 
  From: Ian Service 
  To: [email protected] 
  Sent: Thursday, March 22, 2007 10:39 AM
  Subject: [on-asterisk] Cisco oddity with conference using only g729 enabled


  Okay, here's a good one...

  If you take a Cisco and make it g729 only, dial call one on line one, then 
press Conf, dial another call, it won't connect.  You get a reorder 
message/tone and the console shoots out "No compatible codecs!" 

  So I thought, sure, I guess that makes sense only one g729 call per line on 
the Cisco, I guess that makes sense.  But, you can pick up line 1, make a g729 
call, put it on hold, make another g729 call, put it on hold, go to line two 
and do the same thing, your console will show all four g729 calls at once, 
though I guess you're not talking on any at the same time, so maybe that's the 
loop hole. 

  Anyway, I could enable ulaw to make the conferencing work again but if you 
have ulaw enabled at all, it seems to force the calls to go ulaw first even if 
g729 is first in priority in the show sip peer xxx output.  So you lose the 
whole benefit of using g729 and saving your bandwidth completely. 

  So, is there a work-around to make g729 work all of the time except when I'm 
conferencing or make it work all of the time, period?

  Also, I've only tested this on a 7940, so a 7960 may not have this issue. 

  Thanks in advance for any advice

  - Ian

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