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T-Mobile@Home - using a WRT54G-TM - proposed connection to SPA3102

libratsio
Level 1
Level 1

I researched what I could prior to buying - but now I'm unable to find the thread that directed me to the SPA3102 originally.

I'm using a WRT54G-TM with the T-Mobile@Home VOIP service built in.  There is a SIM card inserted into the router, this serves as the VOIP authentication for my VOIP dialing plan.

I purchased the Linksys (Cisco) SPA-3102 with this thought in mind:  connect (bridge/link/etc) my T-Mobile@Home service with my "ma bell" service - so I could dial one number to "bridge" to the other - either by programming the SPA-3102 to speed dial for me, or to allow manual number entry after a PIN is entered.

I understood (apparently incorrectly?) that the SPA-3102 has an FXO and and FXS port - which would allow me to connect one line to my "ma bell" line, and the other to the WRT54G-TM phone connection (both essentially have dial tones).

I am now realizing through further research that I need to establish a "back-to-back" setup - in that I will need to purchase another device and then link up that device to my SPA-3102 - then I should be able to program what I want done.

First question - can the SPA-3102 be programmed by itself to connect to two live phone lines, one "ma-bell" and the other a "phone" connection on a VOIP device?

Second question - what would the recommended device be to "back-to-back" connect to my SPA-3102?

Third question - where should I start to read on programming the SPA-3102 (and the other device)?  I've found a lot of info - but no real starting point to actually understand what to do....  I also realize answering the third question with a good starting point could actually answer questions 1 and 2.....

Techical, but a newbie

5 Replies 5

Patrick Born
Cisco Employee
Cisco Employee

Hi libratsio,

I understood (apparently incorrectly?) that the SPA-3102 has an FXO and and FXS port - which would allow me to connect one line to my "ma bell" line, and the other to the WRT54G-TM phone connection (both essentially have dial tones).

No, you understood correctly. It has both an FXO and an FXS port. The FXS port allows you to connect an analog phone [not an IP phone]. The FXO port allows you to connect to a PSTN line [like your house's wiring that connects to ma-bell]. The web-UI > Voice tab > Line 1 tab > Proxy and Registration section allows you to configure the SPA3102 to receive services from an ITSP. The SPA3102 becomes the "glue between the two"

First question - can the SPA-3102 be programmed by itself to connect to two live phone lines, one "ma-bell" and the other a "phone" connection on a VOIP device?

Yes, the SPA3102 gets dial tone from a connected PSTN line connected to the LINE port of the SPA3102. It can be configured to register to a VoIP provider called an Internet Telephony Service Provider [ITSP]

Second question - what would the recommended device be to "back-to-back" connect to my SPA-3102?

I'm not sure of the goal of this, so I can't help much here. Hopefully others from the community will add to this thread and help you out.

Third question - where should I start to read on programming the SPA-3102 (and the other device)?  I've found a lot of info - but no real starting point to actually understand what to do....  I also realize answering the third question with a good starting point could actually answer questions 1 and 2.....

This is a list of what you'll need: https://www.myciscocommunity.com/docs/DOC-2149

Regards,

Patrick

-----------

The T-Mobile@Home is an ITSP - but I believe it requires that their equipment be used to access the service (which is another Cisco/Linksys device - the WRT54G-TM).  In that device goes their SIM card.  On the WRT54G-TM is either an FXS or FXO port (not sure which?) by which the VOIP is used.

I recall reading that the SPA-3102 would be the "glue between the two" services - but I understood that it would be the glue between as devices, not necessarily services.

My intention is to take the T-Mobile@home router out of the US - connect it to an Internet connection and be able to use it to call out of the country back into the US.

I also have a phone line outside the US.  My intent was to link the T-Mobile@home service to that phone line - so I could make and recieve phone calls to/from people in that country as a local call when I'm back in the US.

As I understand it now - I think I will need 2x SPA-3102 - one for each phone connection (or I need to change my VOIP provider to someone that I can link to my first SPA-3102).  With my 2x SPA-3102 - link each of the SPA-3102s to each other (as a bridge?).  A PAP2T is another device with a "line" connection on it - wondering if it would do the same thing, and/or be more easily configured to do what I'm trying to do.

I think for this discussion - my t-Mobile@home is not really a VOIP - its another phone line.  Clear as mud?

It looks to me like the T-Mobile solution is basically an analog telephone adapter (ATA) allowing you to use an analog phone for VoIP.

This is similar to what the Cisco SPA ATAs do, except that some of our ATA also provide PSTN gateway functionality between the ITSP and PSTN phone numbers.

Granted T-Mobile is an ITSP, but you'll need an ITSP that supports bring your own device (BYOD) in order to register the SPA3102.

Regards,

Patrick

------------

T-Mobile@Home is not using SIP but a mobile technology named UMA. This is not VoIP, but mainly an emulation of your mobile device over the internet (that's why it has a SIM card).

- Basically you need two FXO ports on the new device (one for the PSTN line and another to connect to the T-Mobile@home router FXS port). SPA3102 has only one FXO port, so it cant do the deal alone, you would a second SPA3102 and then back to back them, i.e.

- Connect SPA3102(1) FXO port to the PSTN line

- Connect SPA3102(2) FXO port to the T-Mobile FXS port

- Connect the anlog phone to the SPA3102(1) FXS port

- Configure SPA3102(1) dial plan, so that when you press 9 it goes to PSTN (gw0) and when you press 8 it goes VoIP.

- Configure SPA3102(2) VoIP-PSTN gateway so that incoming calls through VoIP goes over PSTN.

- Configure SPA3102(2) PSTN-VoIP gateway so that incoming calls through PSTN goes over VoIP.

- Configure both SPA3102 Line 1 to have the VoIP information of line 2 (Proxy = IP address).

This configuration is not simple if you dont know about VoIP. If you are not savvy on it, I would discourage you perform this config as it requires fine tunning and knowledge on how the SPA3102 operates. The ATA Administration Guide (check the documentation area) has all information about the SPA3102 advanced configuration.

Regards
Alberto

Roger that.

I bought a second SPA-3102, should be delivered tomorrow.

You are correct - it is UMA - which I've heard described as "GSM over IP"

I'm not sure I need to configure it too much - as when I'm actually on site - I will have the equipment disconnected and use each line separately - one for in-country dialing, the other to "phone home" back to the US.  When I travel back to the US - I should be able to call my T-Mo@home # - connect to the SPA-3102 - #1(connected to the T-Mo) - which will forward me through the back to back connection to the SAP-3102 - #2 (connected to local line) - at which point I haven't decided how to program it.  I may have a PIN or speed dial options, or just get a dial tone.  Also - people in-country could dial my local line - which I would like to program to dial my home # here in the US.

Relatively low risk - even if I can't figure it out exactly as I want it - it may be rocket science, but I won't be losing any lives trying to do it myself....

Thanks for the feedback.

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