If you are having problems making all the jacks in your house "live" with your U-verse dial tone, if you follow the directions below you can make this happen.  This method will not work if you still have POTS service working in your home, although it is possible to keep a POTS line working, just not with the wiring methods discussed below.

This wiring method also does not take into consideration alarm systems.  In my case, my alarm system is connected with a GSM cell phone network connection, so I am not worried about connecting my alarm into my U-verse dial tone.  I highly recommend this method of connecting alarm systems to central stations.

And, lastly, this method is for U-verse service that is connected to the home via a copper loop.

There are different styles of NIDs, and I suppose it is possible there are still even some homes that do not really have a NID, but just have a protector, so you must be sure you do not do anything to bypass the protector or NID's circuitry or you could end up with inside wiring that is not protected against surges.  If you are not comfortable that you can be sure you will not compromise the integrety of the NID/protectors surge arresting capability and other functions, you need to arrange for professional installation.

If your home is wired with Cat-5 or Cat-3 this should work.  If your home is wired with the older "quad" wiring, which is wiring with a green, red, yellow, and black wire, that are not twisted together, I do not know if this will work or not.  It might work if the quad wiring run  to the RG is very short.  But in this case, it would be highly recommended for you to run a new Cat 5 cable from the NID to the RG.  You can still use the red/green/yellow/black "quad" wiring for your phones.  More on this below.

I have tried to be as comprehensive as possible to cover all wiring situations that you may encounter, so this probably will seem more complicated than it really is.

First, at your NID, or in rare cases if you have an older installation, at your "protector", if you have a feed from "the street" that has more than one pair of wires, determine which pair of wires from the street is being used for the U-verse service.  For example, if you have two or more pairs coming in to your NID/protector from the street, and, say, the orange/white pair is connected through the NID/protector to the blue/white pair of your inside wire, and you plug in the U-verse box to a phone jack and it syncs up, you can be 99.44% sure the orange/white pair from the street is the pair being used.  If it does not sync up, be sure there are no phones, faxes, etc., plugged in to any of your jacks.

Now, still at the NID/protector, connect a different pair of the inside wires to the wires from the street.  In the above example, connect, say, the orange/white pair of inside wires to the orange/white outside wires.  Be sure the blue-white pair is not connected to anything at the NID/protector, and the ends are taped to keep them from inadvertently coming in contact with other wires or terminals.  And, hook up a tag to the blue/white pair that says something like:  "this pair of wires is disconnected because they are connected to a VoIP residential gateway located within the premises."  It would be a good idea to have all unused inside wires isolated from the wires coming in from the street.

While you are at the NID or protector, be sure the solid copper ground wire is securely connected to the NID and ground rod which should be located nearby.

Next, you will need to determine the configuration of your home's phone wiring.  Often phone wiring is daisy chained from one jack to the next, and there could be a jack where a wire (usually NOT the blue/white pair) is not connected through to the next jack.  And sometimes the wiring is wired in a star configuration.  This is where each jack has a home-run to a central wiring location, and usually only the pairs needed for whatever service you had at the time of the initial installation are connected. 

Now, at the jack where you will connect the resdiential gateway, install a double wall plate or otherwise install two jacks.  

At the location where you will install your RG, if your wire is of the "daisy chain" configuration, wire  the "incoming" orange/white pair to the Red and Green terminals of the first jack.  Leave the "outgoing" orange/white pair disconnected so as to avoid creating a "bridge-tap".   Connect the green cable to the residential gateway to this jack.  (You may not know which of the orang/white pair is incoming and outgoing, but can determine this by experimentation. If the first pair does not work when you power up the RG, below, try the other pair.) 

If your wiring is of the "star" configuration, find the cable that feeds the location where you will be installing your resdiential gateway, and connect one pair, say the orange/white, to the Red Green terminals of the first jack.  Back at the other end of this cable, be sure it is the only cable connected to the incoming pair that has the U-verse signal that you connected through at the NID/protector, or you will create "bridge-taps" that may slow down or interfere with the U-verse signal and cause you problems.  Plug in the green cable to the residential gateway to this jack.  Connect the blue/white pair of this cable to the R and G terminals of the other jack and be sure the blue/white pair is connected, back at the central location, to the other home run cables where you want dial tone.

After making these connections, power up the RG to be sure it syncs to the U-verse signal.  If it does not, you have done something wrong, or (in the case of daisy chanin wiring) you may have something plugged into one of the jacks, such as a two-line phone, that is interfering with the signal on the orange/white pair.  Be sure this is not the case.  If you have daisy chained wiring you may want to disconnect the orange/white pair from all the other jacks in the house if you have this problem.  If you do this, be sure to maintain the continuity of the orange/white wires, using splicing connectors, so the signal reaches the RG.  And, if the pair of wires, in my example the orange/white pair, is not connected through at each daisy chained jack prior to the jack that is connected to the RG, you will have to find that problem and make the appropriate splices.

Once you have the RG synced up connect the blue/white inside wires to the second jack, and connect this jack to the RG's Phone port.  You should now have dial tone at all the phone jacks in your house.

This will also work if you are using both lines from the RG.  But in this case, you will need inside wire with three pairs (typically Cat 5 wire with four pairs, but I have seen Cat 3 wire with 3 pairs), and follow the basic instructions above.

If you are using both lines and your house is wired with just two pair cat 3 wire, or with the old red/green/yellow/black "quad" you can install a new cable from your NID/protector to whereever the RG is located.  In this case, run a new Cat-5 cable from the NID to where the RG will be located, and at the NID connect one pair of wires to the pair from the street that you have identified as having the U-verse signal.  At the RG end of the cable connect that pair to the R and G terminal of a jack and plug in the green cable going to the RG.  Isolate all the existing unused wires coming from the house to the NID (and tag them as discussed above) and plug in another cable from the Phone 1/2 jack on the RG to your existing inside wiring as discussed above.

Beware that if you use both lines with quad you will likely hear cross-talk between conversations on line one and two that is so strong you may be able to understand parts of the conversation on the other line.  This is because the wires in the quad cable are not twisted.  Quad was not designed for two line service; rather the yellow/black pair was for low voltage for lights on the original trim-line phones, etc.  The longer the quad cable, the worse the crosstalk will be.

If you still have POTS working, then everything is much more complciated, and you will may need filters or more complicated wiring.  The above will not work if you are still using POTS.  And, again, be sure you are comfortable that you will not defeat the purpose of the NID/protector.

Good luck!

(I am an "Old Phone Man".  I do not work for AT&T, and never have, but Ihave worked for an independent phone company in the past.)