This is something that comes up periodically, and whether you can do it easily depends a little whether you are using CCA or CLI to configure the system. Essentially the wya this is done is as follows:
- Create a collection of shared lines equal in number to the number of calls supported on the SIP trunk. So if the trunk (or the underlying WAN bandwidth) supports four simultaneous calls, then you need four shared lines.
- Configure the first shared line to be the target of calls incoming from the SIP trunk, and then link the shared lines using call forward busy so that an incoming call will roll from the first line to the second, then to the third and so on until it finds an available line to ring on.
- Configure the dialplan so that calls outbound from those shared lines do not require an access code to be dialed.
- Assign the shread lines to buttons on the phones in the same way you would assign trunk lines if you were using analog lines.
- Typically you would also assign the first button on the phone to be a dialable intercom for internal calls.
This is relatively straight forward using CLI for configuration, but unfortunately, cannot be done completely using CCA yet. Specifically, step 3 is not yet supported in CCA, and neither is step 5. Support for dialable intercom (step 5) should be available very soon, but step 3 will remain a gap for a little while yet. If you follow the OOB configuration guidelines, you should be able to set almost all of this up using CCA, and then assign an inbound translation pattern on the shared lines that prefixes an access code onto the dialed number of calls placed on the phone which would address step 3. That would keep the non-CCA configuration to a minimum.
Cheers,
Dave.
