Best way to implement new IP phone system using PRI

telextech used Ask the Experts™
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.
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I am not familiar with any of your potential gear, but assuming your descriptions of your potential equipment are accurate, of the top of my head I'd go with solution 2, since that gives you the maximum FXS ports.

"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."

It's been over 10 years since I had to handle PRIs, but IIRC the dynamic channel allocations are a function of the PRI service, not the edge equipment.  

Go with solution 2 - solution 2 replicates the existing config, and saves $$.  You can implement more complex solutions once the initial migration is complete.

You can do away with the fax server all together and just buy the pri cards for the Trixbox.  Then install Hylafax or advantFax on the Trixbox.
I think I'd have to go with Jordanlcn here. Either method requires buying an interface card. Install a Digium TE121 (PCI-E) or TE122 (PCI) interface depending on your server architecture. I would recommend using PRI instead of a T1 though. The advantages are caller ID comes in before the ring, any number can come in on any channel meaning that you can handle multiple calls to the same number, and outgoing caller ID is simplified. I would also install Hylafax/IAXModem on the asterisk box and eliminate the fax server. If you just have to keep the fax server, you can use either a TDM800 card with two quad FXS port cards or an external SIP to analog gateway such as a Mediatrix 4008 or Grandstream GXW-4008 to provide analog lines to the fax server. You can then route the fax calls through the gateway to the fax server. We use the Hylafax for several of our customers. The ability to use it for fax to email and print to fax has saved our customers money by not having to maintain a separate fax server.


I believe all were good answers. Sorry for the delay, I'm still figuring out how this site works.
Qlemo"Batchelor", Developer and EE Topic Advisor
Top Expert 2015

This question has been classified as abandoned and is being closed as part of the Cleanup Program.  See my comment at the end of the question for more details.

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