Hi :) We currently have a single * box with 4-port E1 card terminating 60 channels: [PSTN] | | 2 x E1 [Asterisk] | | 2 x E1 [Legacy PBX] What I'd like to have is this: [PSTN] | \______ | | [*1]- - - -[*2] - DUNDi peering between 2 * boxes | | [Legacy PBX] Whereby a call in either direction would be routed either 'straight through' to/from the PSTN from/to the Legacy PBX, or in the case where all channels were in use (we max out at about 40-45 channels usage), it would connect via IAX to a free channel on the other * box. This is slightly different from the DUNDi tutorials I have found on the web (including markster's excellent one on voip-magazine.com) whereby DUNDi is only consulted if 'is this extension local?' fails. In my case, both sets of extensions are local to both boxes, but I want to utilise any spare capacity on the other machine. Also, I am not using any SIP devices here, only Zaptel ones. Should this be as straightforward as replacing our current 'Dial' entries in extensions.conf : exten => _31.,1,Dial(Zap/G2/${EXTEN}) with a 'DUNDi-aware' version like: exten => _31.,1,Dial(Zap/G2/${EXTEN}) switch => DUNDi/priv How does this deal gracefully with the scenario of 'no free channels' ? Is there much variance in DUNDi between 1.2.X and 1.4.X ? Cheers, Gavin.