[asterisk-users] Asterisk connection to a PBX

[asterisk-robert]

We are thinking of setting up an Asterisk system to route calls between 2 of our factories. Our idea is to connect an Asterisk box to each PBX and then use SIP(or IAX) to truck between the 2 systems on our internal network.  

I would be interested in any ideas regarding the connection points: 
1. Is using Asterisk a good solution?
2. Is using a T-1 card the best way to connect the PBX and Asterisk?
3. If analog is used for the connection is it better for Asterisk to use FXO or FXS cards?

Any ideas are appreciated.

Robert