[Asterisk-Users] DID trunks -- equipment requirement

[Josh Rollyson]

>Hi guys,
>
>
>I'm looking to setup a 16 extension / 10-14 phone line Asterisk install

>for a customer who would like to have DID numbers for the extensions, 
>since they're currently on Centrex and already have the 1-to-1 
>correspondence.  Since I'm in a less populated area of the country, SBC

>doesn't seem to have much in the way of fractional T1 products (on the 
>scale that we need them) available, so I think my only option for DID
is 
>to use (analog) DID trunks for incoming calls and POTS lines for 
>outbound calls.

I'd look into ISDN, both PRI and BRI. If the costs are not too
prohibitive, this would be the most flexable option. ISDN uses out of
band signaling and has a number of features which complement a DID
enviroment, such as DNIS (dialed number information service), where the
number dialed is passed along with an incoming call. If your enviroment
never uses all its outside lines at the same time, this can be cost
effective, because you can have direct dial numbers for all the phones
without a one to one correspondance of outside lines to extensions. PRI
is usually too expensive, but sometimes BRI is affordable, however you
should check on pricing for both to see if they may be cost effective.