Solved: How To: Use single T1 for voice and Data using FX(S|O)

ecornwell · ‎11-30-2007

Hello,

We currently have some old and hard to use Vina routers installed that allow us to send/receive calls and data between our remote site and our main site. The routers either have fxo or fxs cards in them depending on which site they are in.

At our end, a couple lines come off our PBX to the router along with a network connection and a T1. We have a T1 to the remote facility where it terminates into the router and splits the connection back out. (The remote facility has the fxs card.)

We would like to upgrade the equipment and use Cisco devices but I've been unable to figure out what hardware we would need and how to configure it.

We have considered using VoIP but we have reasons that we don't want to.

Can someone help?

Thanks!

Eric

paolo bevilacqua · ‎11-30-2007

Hi, VoIP means that the voice signal is digitalized, then encapsulated in an IP packet, and sent over an IP network. This is the current technology used by all cisco products with few exceptions.

As mentioned before I recommend an ISR router and not the IAD that is targeted for service providers.

The router can be as small as 2801 voice bundle, plus 2 x VIC-4FXS/DID, and WAN card as necessary.

Remember that you will always need something in the hub site as well, to reconvert VoIP to analog FXS, FXO or whatever interface you need to use.

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paolo bevilacqua · ‎11-30-2007

Hi,

if you only mean of connection to you voice insfrastucre is via analog ports like FXS or FXO, all cisco products use VoIP to carry the calls over a data circuit. That is, they do not work like certain tdm-like legacy devices in which a portion of bandwidth was used for voice and other for data.

If you had a T1 digital interface for voice to the PBX, it would be different and VoIP not be mandatory, but you are telling us that is not the case.

If you could tell us what are the reasons for you not to use VoIP, we could see if there is any solution for your concerns.

imran_mo · ‎11-30-2007

You can go in for Cisco IAD 2430 that can serve the same functions for you.

http://www.cisco.com/en/US/products/hw/gatecont/ps887/products_data_sheet09186a008019aded.html

HTH.

Regards.

paolo bevilacqua · ‎11-30-2007

Worth to note, the IAD2430 is VoIP based with added features for service providers, and doesn't support FXO interfaces. It doesn't really fit enterprise market for which ISR router are recommended.

ecornwell · ‎11-30-2007

What do you mean that it is VoIP based?

Right now we are running through a couple options.

1. Direct Replacment - From a quick look it looks like that would be 2 - IAD2430-8FXS. (One at either end.)

2. ISR 2821 with a WIC-1DSU-T1-V2, EVM-HD-8FXS, and a PVDM2-32 (using the voice bundle.)

With option 2, we could bring the existing T1 into our Core router and not have to purchase hardware for this end. Then the remote end would basically remain the same and all calls to the facility would be voip.

paolo bevilacqua · ‎11-30-2007

Hi, VoIP means that the voice signal is digitalized, then encapsulated in an IP packet, and sent over an IP network. This is the current technology used by all cisco products with few exceptions.

As mentioned before I recommend an ISR router and not the IAD that is targeted for service providers.

The router can be as small as 2801 voice bundle, plus 2 x VIC-4FXS/DID, and WAN card as necessary.

Remember that you will always need something in the hub site as well, to reconvert VoIP to analog FXS, FXO or whatever interface you need to use.

ecornwell · ‎11-30-2007

The goal was to get the call to our PBX. We currently have a Voice Gatway with a T1 to it for the rest of our VoIP deployment.

(There were some concerns with VoIP for this specific site and as always a little politics mixed in... :) )

It looks like we'll go with the ISR solution.

Thank you for your help!

paolo bevilacqua · ‎11-30-2007

Hi,

you will be fine with VoIP. Remember, the only two things that are "hard" to do with VoIP, are Fax and Modem. All the rest is a breeze with a little study and application. Beside, the 2801 supports up to 24 IP phones for a full-featured PBX called CME that runs in IOS.

Thanks for the nice rating and good luck!

ecornwell · ‎11-30-2007

Thanks for your help. We actually have about 400 Cisco phones installed and being used in different parts of our company. We just had this one case where legacy support was wanted. We had looked at going full VoIP for the site but that was shot down quickly. (They have a key system and didn't want to give up certain control they had and didn't want to pay for VoIP.)

paolo bevilacqua · ‎11-30-2007

Sure, the technology comes with a price

This is also the reason why I suggested the smaller 2801 instead of the 2821 with the EVM that is more expensive plus it require two external parts (patch panel and cable) to be put in place.

Although the 2821 it's an excellent platform to support in the future, like 72 IP phones with CCME.

In this perspective, you can give to a local administrator the possibility of maintaining the telephony part using the GUI, while you retain the overall router control.

Good luck in any case!

scottmac · ‎12-01-2007

There are ways to define channel groups to divide a router-terminated T1 into "these channels (DS0) do voice"(TDM) and "these channels (DS) do data" Some of it depends on the router and interfaces.

What may be easier for you, and more traditonal, might be to use an Add/Drop CSU/DSU (sometime called a "Drop and Insert" CSU/DSU).

It would be an external device with one T1 port (RJ48) and (at least) two other ports: One for the data, usually a V.35 serial, and a second port for passing the non-data channels (DS0) to your PBX.

You configure the CSU/DSU for how many channels/DS0s go to each port.

Please note that you need to do exactly the same channel split on both ends, or nothing will work.

You could possibly do the a similar thing with a mux / channel bank, but Add/drop CSU/DSUs are probably cheaper and easier to deal with conceptually, since you can "see" the physical split happening at the CSU/DSU.

You might also want to check out something like an Adtran Total Access 850 or Total Access 612 or 624. THe TA series can take a straight-up T1 and break it into X DS0s of voice (FXS POTS voice, delivered to a 66 block)) and X DS0s for data (delivered to an RJ45), and they're also fairly inexpensive.

Good Luck

Scott