Here's a description, and I'll try to be brief.
Call Manager 4.1
2821 router
T1 (2 port) Multi-Flex Trunk WAN daughter card
We're finding that inbound calls from the PSTN that are forwarded back out to the PSTN will generate a ring for the called number, they answer, no audio. On the calling end, they hear ring no answer.
So, I believe this will be a problem with the T1 in question, but I don't know what the problem is.
Also of note... forwarding internally and externally from inside works. So it's only a hairpin call that triggers condition.
The following is some of the configuration involved for this card.
no network-clock-participate wic 3
controller T1 0/3/0
framing esf
clock source internal
linecode b8zs
channel-group 0 timeslots 1-24
controller T1 0/3/1
framing esf
linecode b8zs
channel-group 0 timeslots 1-24
interface Serial0/3/0:0
no ip address
encapsulation ppp
ppp multilink
ppp multilink group 1
!
interface Serial0/3/1:0
no ip address
encapsulation ppp
ppp multilink
ppp multilink group 1
The interface is reporting errors.
Thanks for any feedback!