Our company (a local ISP) is willing to buy a UC520 bundle with 4 BRIs and 4 FXS for analog telephones and FAXes.
We plan on having 30 Cisco IP Phones. No teleworkers. Multiple SIP trunks and B-ACDs.
The idea is to start using 2 BRI to receive/send calls and faxes with our existing PSTN numbers. Next we'll buy a dozen of SIP numbers (every account/number has a different username/password but they're with the same provider) to realize a semi-keysystem where some SIP numbers are directly put to the phones. These phones have obviously internal numbers too and are 7906G.
Next, up to 10 outgoing calls must use an additional SIP trunk and the exceeding calls are to be routed to the ISDN BRIs if available. If needed, with a different prefix anyone may choose to be routed to the ISDN for the outgoing calls. This is a matter of precedence and destination patterns, right?
Now the toughest part for me.
When an incoming call to any of the BRIs or to a specific SIP number (obviously not one that is directly overlaid to phone button, but probably the one used to make outgoing calls) must be sent to a hunt group (likely parallel), if no one is answering in 20 seconds a B-ACD takes over putting the call on queue and continuing the parallel hunt. I'm not sure if this behaviour for the B-ACD is possible.
An analog FAX on a FXS must pickup the first free ISDN BRI line, so no intermediate tone of the PBX. I think it's called PLAR. Am I right?
Last thing. After hours anyone from any phone may enable another B-ACD that answers any incoming calls saying that the office is closed.
On the multiple SIP trunks I've found some resources that I cannot verify but seem to blend nicely with my specifications:
Can you help me? I'll share with you the final and intermediate stage of configuring this system, and as soon as my expertise grows I'll try to fit in this community :-) I currently hold the CCNA and working on the last 2 exams for CCNP.