At a customer site I have installed an UC540 with one dualline isdn2 trunk and a SIP trunk configured. Incoming phonecalls are handled correctly. In my config outgoing phonecalls depend on the priority of the dial-peer (sip or pstn) whether the phonecals go out via SIP or pstn.
Is there a way to route one ephone through the SIP trunk and an other through ISDN? (CCA or CLI)