Need to add Linksys WRT54G-TM wireless router with Linksys SPA 2102 phone adapter

It is not possible because you need an ISP provider like a DSL or other type.The telephone line is only for voice not data.

What I have understand from your question is that you just want to get your VoIP device working but probably you may need a SIP account from a VoIP service provider.

Turn DSL-router off.
Turn Actiontec off.
Turn computer off.

Connect:

* telephone-port in wall <--- 4-pin telephone wire --> DSL router

* Ethernet port on DSL-router <-- Ethernet cable --> WAN port on router

* One of the LAN ports on router <-- Ethernet cable --> network-port on your computer.

Turn DSL-router on, and wait for it to fully load, i.e., pattern of lamps becomes repeatable.

Turn Actiontec on, and wait for it to fully load, i.e., pattern of lamps becomes repeatable.

Turn computer on, and boot it.
Click Start
Click Run
Type CMD
Press Enter
Type IPCONFIG
Press Enter
Look for output like: Default Gateway....192.168.123.456
Start Internet Explorer
Type http://192.168.123.456 (or whatever numbers you saw)
Login to your router
Configure the wireless adapter inside the router
(enter an SSID, choose 'WPA' encryption, enter a password)
Disconnect the Ethernet cable from your computer
Click "View Available Wireless Networks",
and select the SSID that you provided.
Enter the password that you provided.

>No, it really doesn't matter what type of service you have.
>To get it fixed just make sure that if your mom uses a modem and you hooked the router to it, modem must be in BRIDGED mode before you can make the router work.
>To set the modem to bridged mode you need to contact your mom's DSL provider so they can walk through it

In the diagram below, if this is your setup, modem has to be on Bridged Mode:

Phone jack --- modem --- Linksys Router --- computer

More information is needed about your setup.

Do you have:

cable modem <--> router <--> computer
and:
cable-telephone-box <---> telephone

or:

DSL-modem <--- VOIP adapter --> telephone
and VOIP adapter -> WAN port on WRT54G <--> computer

Please clarify.

If you want to receive "incoming" telephone-calls:

ADSL modem <---> Linksys SPA <---> wrtu54g <---> wired computer

and Linksys SPA <--- telephone-line-1 --> telephone hand-set
and Linksys SPA <--- telephone-line-2 --> FAX machine

or Linksys SPA <-- telephone-line-1 --> mechanical telephone-splitter
with telephone-splitter --> hand-set
with telephone-splitter --> FAX

Hi i have found some useful information ...
PLease click on the link;

http://linksys.custhelp.com/cgi-bin/linksys.cfg/php/enduser/std_adp.php?p_faqid=4963&p_created=1168254340&p_sid=Dr5KyRBj&p_accessibility=0&p_redirect=&p_lva=3687&p_sp=cF9zcmNoPTEmcF9zb3J0X2J5PSZwX2dyaWRzb3J0PSZwX3Jvd19jbnQ9MjgsMjgmcF9wcm9kcz0wJnBfY2F0cz0xNzIxLDE3MjMmcF9wdj0mcF9jdj0yLjE3MjMmcF9zY2ZfMz0xJnBfcGFnZT0xJnBfc2VhcmNoX3RleHQ9Y2FzY2FkaW5n&p_li=&p_topview=1

Or thry this second option

http://linksys.custhelp.com/cgi-bin/linksys.cfg/php/enduser/std_adp.php?p_faqid=4579&p_created=1165892402&p_sid=Dr5KyRBj&p_accessibility=0&p_redirect=&p_lva=3687&p_sp=cF9zcmNoPTEmcF9zb3J0X2J5PSZwX2dyaWRzb3J0PSZwX3Jvd19jbnQ9MjgsMjgmcF9wcm9kcz0wJnBfY2F0cz0xNzIxLDE3MjMmcF9wdj0mcF9jdj0yLjE3MjMmcF9zY2ZfMz0xJnBfcGFnZT0xJnBfc2VhcmNoX3RleHQ9Y2FzY2FkaW5n&p_li=&p_topview=1

I have att yahoo dsl which I installed about a year ago. The process required bridging the ADSL Modem (in my case a speedstream 4100) and accepting dynamic IP addresses and configuring PPPoE on the WAN side of my Linksys router. The ATT support person walked me through the entire process over the phone even though I was comfortable with making the Linksys configuration changes as I had to do the same in China without technical support. The modem configuration was no more difficult than the router configuration as it was performed from a web browser too. The biggest warning was that to reverse the modem change (if desired) required use of a reset button because the web interface was disabled as a result of the configuration change. My advice to you especially if you are willing to attach the Linksys router to the telco modem is to contact the ATT highspeed DSL support line and see if they will walk you through it like they walked me through it. Reviewing your Linksys User's Guide and understanding the configuration of that device would probably be appreciated by the ATT Support person as well as assuring you can access the Linksys router to configure it during the call.

When dealing with a router there are multiple IP address scenarios, on the internet service provider's (ISP) side you can have either a static or dynamic IP address. I believe most routers by default are set to accept a dynamic IP address from the ISP. Where the ISP permits the router can also assign IP addresses to each device that attaches to it allowing a single ISP connection to be shared by multiple computers. This is also generally the default for routers purchased for home use and the wireless adapters also accept the dynamic IP assignment from the Router. With the logical discussion out of the way I believe you wish to discuss the physical connections to be established. Again this is a generic discussion not knowing your specific environment. port types - I will refer to phone ports (technically RJ-11 either two or 4 wires (these cables plug snugly into phone jacks and modem connectors) and ethernet ports (technically RJ-45 which are 8 wires and to big to fit in phone and modem ports) First you have a connection provided by the ISP for DSL this is your phone line where filters are attached to your voice phones and an unfiltered phone connection goes into the DSL modem's phone port often with an ethernet port. If you have cable generally the cable company provides a connection to a cable modem which has an ethernet or other port to connect to your system. The ethernet port generally connects to the wan port (generally separate) of your wrt54g router with an ethernet cable. Computers can be attached to the wrt54g router using the 4 ethernet ports in a group provided they have an ethernet port too. Wireless cards connect to the wrt54g router through radio waves and with antennas on the router and often internal to the wireless adapter (often embedded in a notebook computer today). These details are enclosed with your ISP's instructions and the Linksys router instructions often with pictures to help the explanation.

see
http://www.linksys.com/servlet/Satellite?c=L_Product_C2&childpagename=US%2FLayout&pagename=Linksys%2FCommon%2FVisitorWrapper&cid=1149562300349
if you do not have the user manual.