We have a 2811 with:
1 ISDN PRI
4 FXS ports
3 SIP Peers (asterisk)
Calls are working fine, calls come in from the PRI and from SIP peers and get routed to the FXS ports
However, when all 4 FXS ports are busy, the 2811 is returning a Congestion on the PRI, and a 500/internal error to the SIP peers.
How can I make this be busy instead?