I have a customer who is paying $1,100/mo for 18 POTS lines (8 of which are dedicated fax lines). AT&T quoted us $690/mo for a T1 PRI w/ 23 channels. I've determined this will save them some money as well as allow for better utilization of the channels. They have 8 dedicated fax lines because certain employees have their own fax machine. They aren't all constantly sending or receiving faxes.
I've came up with two possible plans:
1. Get an Adtran Total Access 608. This provides me with 8 analog FXS that I will bring into the new fax server (going to be replacing individual fax machines). I will then buy a Sangoma A142 Synchronous Dual Serial Card that will go into our Trixbox. This card will plug into the Adtran Total Access 608 via V.35, allowing us to use the T1 PRI for voice calls as well as faxing over the Adtran's FXS ports.
2. Get an Adtran Total Access 624. This provides me with 24 analog FXS ports. I will wire 8 to the fax server and the remaining into an analog POTS card in the trixbox.
From what I understand the first solution would be more dynamic. Like if only two fax machines or busy the unused lines that are going to the fax machines could be allocated to a voice call.
I may be wayyyy off on my ideas, but hopefully someone out there can say either yeah solution 1 is awesome and will work, can suggest changes, or even suggest a new plan. I'm open to anything. I've installed alot of small VoIP systems but I haven't really messed with T1 PRI's much.