LukeIn order to make that call ring on multiple phones you just ahve to assign that dn to different phones. In that case it becomes a shared line between the phones.For calling out through your FXO line from any of the phone, you need to have a pots ...
Is the PBX supposed to take clock from the Router. When you configure the clock source internal your router will be providing the clock to the PBX. What other options do you see for clocking under the T1. Have you tried changing the clocking options.
Check out the following document. According to Cisco CallManager can work with SIP endpointshttp://www.cisco.com/en/US/products/sw/voicesw/ps556/products_administration_guide_chapter09186a00801ec5cd.html#77849
