[Asterisk-Users] Cisco 79XX - Using built-in 3way conference

[Kevin P. Fleming]

Matthew Boehm wrote:

> This works fine if caller 1 and 2 are both other phones in the office or
> caller 1 is a phone in office and 2 is PSTN. Just doesn't work when both
> PSTN. Worked before..

What codecs are involved? If you are using low-bandwidth codecs for PSTN 
connections, the Cisco phones will refuse to conference two 
low-bandwidth calls together. They may work with a ulaw and a 
low-bandwidth call, but I haven't tested that.