Using Airport Express with an ATT DSL router

Question

July 10, 2012
Hi All! The following thoughts are for
     1) those of you who use ATT DSL as your internet service-provider, and
     2) who wish to stream iTunes songs from your computer to speakers in other rooms via AIRPORT EXPRESSes, and
     3) are wondering whether you have to purchase a separate Apple Airport Extreme base-station, or can simply use your exisiting ATT router.
Having just spent several days and many hours on the phone before Apple's tech "Dan" was finally able to get my system up and running, I thought some of you might appreciate my sharing the following info while it's still fresh in my mind.
1. You may need to update your ATT router to the latest version, in order for it to properly communicate with your AIRPORT EXPRESS(es) (henceforth shortened to "AEs").  The AEs use 802.11n speed.  My original ATT router (a 2Wire 2701HG-B) was no faster than "-h,"  and this might have been part of the problem as to why my system wouldn't work.  I went to my local AT&T store, and got their latest router: as of this writing, a Netgear "Westell"  Model B90-755025-15, which can run at both the slower speeds as well as the faster "-n."  To find out some of the specs of my router, an Apple tech had me type in the 10 digits of my Gateway IP Address into the address-bar (no need for the "https://www") and "Presto!", up popped several pages of info on my router.
2. When first setting up your AE, it needs to be back in "default mode."  If it's right out of the box, you don't need to do anything.  But if, like me, you've already made several attempts to get it running, then you need to reset it to its pre-configured state,  You do that by taking a bent paper-clip, and inserting one end into the little hole on the ports-side of your AE (near where the mini-plug of a speaker-cable is inserted). While the device is plugged in, gently press the paper-clip into the hole until the light on top blinks amber QUICKLY, the flashes coming in rapid succession.  Then remove the paper-clip, and the AE will glow solid amber--meaning it's waiting to be re-programmed.
3. When first setting up your AE, do NOT attach an ETHERNET CABLE from the router.  The only cable that needs to be attached is the mini-plug cable running to some sort of portable, powered speaker.  For myself, to make things easier, I brought my AE and my new Sony RDP-M5iP speaker/dock into the same room as my Imac & router. That way, I'd know immediately if the AE was working correctly.
4. After you've clicked on your Airport Utility App (hard drive TO Applications TO Utilities folder), you'll soon come to a page that asks you to name your AE (this page calls it a "base station").  Before you do that, you should see a button in the lower left-hand corner that says, "Other Options."  Click on it.  You'll then be given a choice of "Creating a New Network"  or "Choosing an Existing Network."  You want this 2nd choice--because you indeed are planning to use your ATT router's exisitng wireless network.
5. Shortly, you'll come to the page asking you to name your AE.  Call it, for instance, "Family Room Speaker." As for password, at first I--as well as virtually all of the techs with whom I spoke--thought I should type in the multi-digit ATT router-password (called a "Wireless Network Key").  But finally, "Dan" told me to simply type in, "express1"  (or, for my 2nd AE, "express2").  That did the trick! 
6. Your AE should now be glowing green on top.  Plus, on the 10x6" dark-grey rectangular box displaying the globe (i.e., your main internet connection), the globe should have a now-green glowing circle to its left.  And underneath, it should be displaying a rectangle named "Family Room Speaker" (or whatever name you've given your Airport Express).
7. When you now open iTunes, you should see a little blue rectangle (with a triangle in its middle) in the lower right-hand corner of your iTunes box.  Click on it, and it should show listed both your computer-speaker as well as your AE speaker(s), plus a heading called "multiple speakers."  Click on "multiple,"  and it will bring up a box displaying all your now-current speakers.  Check the small square next to any speakers that are unchecked, and a volume-slider will appear.  Bring them all up to a comfortable level.  Then click on an iTunes track you'd like to play and, viola!, you should hear music playing both from your computer and from the portable speaker to which your AE is attached.
8. Now close iTunes. Then unplug your Airport Express and--if you have a 2nd AE-- plug them both back into your power-strip. Go thru the set-up steps in your Airport Utility App for this 2nd AE.  At the end of it, both AEs should be glowing green on top, and both should be displayed on your computer-screen.
Now re-open iTunes, and start a song playing.  (Don't forget to click on the blue rectangle at the R-hand bottom, and activate the new AE speaker.)  By inserting your speaker cable alternately into each of the AEs, you should be able to verify that, yes, both are now working.
9. Unplug both AEs, and bring them to whatever room you want to use them in.  Plug them in to a wall outlet, and run your mini-cable from the AE to the speaker.  Give the AEs a few minutes to pick up the signal once again from your ATT router; when they do, their lights will change from amber back to green. Tech Dan warned me to keep them away from too much metal, to avoid interference. As soon as they turn green, you should now be hearing your iTunes track playing thruout your house! (If not, you may have to first close iTunes on your computer, then re-open it, and start a new track playing.)
The BOTTOM LINE: no, you don't have to purchase a separate Apple Extreme to be your base-station.  Your ATT router--if it's running at the 802.11n standard--should be able to work with your Airport Express(es)!
My thanks to Sean and Cameron and  Chris and, most especially, Dan, the Apple techs who patiently worked with me to get this system online. 

Answer 1

I am GREATLY appreciative of this overview. Even though I don't understand a lot of it. I will keep working through. I am-- have for 2 years-- had terrible connectivity with AT&T's service & 2Wire router. My MacBookPro keeps dropping the signal. I'm talking every few clicks at times. Husband's PC drops it, too, but not nearly as much as the Mac. I'm sure what you posted can help us get better connectivity.