Today, voice options run from hollering down the hall to instant-messaging around the world. But force of habit kept me paying an outrageous $102 a month to Qwest, my local telco, for two landlines and services like call waiting that former monopolists still wildly overcharge for.

Every time I was on the verge of convincing myself to sign up for cheap Internet-based phone services, something would dissuade me--a Skype convert's garbled calls, a Vonage customer's lament about an all-day service outage, the wails of a friend whose cut-rate phone provider had gone bust.

But T-Mobile recently enticed my inner cheapskate with something that goes by the ludicrous name HotSpot @Home Talk Forever Home Phone. First you buy a special $50 Linksys wireless-G four-port router with two RJ-11 phone jacks that can hook up to standard home phones. A $35-per-line activation fee gets you a SIM card that goes into the router. After that, each line gives you unlimited calling within the United States for $10 a month plus $3.50 or so in taxes and fees.

Drawbacks? Some services that other Net-phone providers offer, like Web-based voice mail and the ability to change call-forwarding remotely, aren't available. Placing an international call is pricey. Faxing doesn't work. Each line requires a two-year contract with a $200 early-termination fee, and you have to pay T-Mobile at least $50 per month for wireless to qualify for landlines, a sneaky way of making you a stickier T-Mo customer. And of course, if you lose your Net connection, you're out of luck.

Still, I plunked down my Visa card and took the new router home. Calls sounded okay. When voice mail came in, my cordless phones' message-waiting indicators lit up. At one point, I had to reboot the router to get dial tones back, but the incoming calls went to voice mail anyway. I was so smitten with the prospect of saving $850 in the first year that I decided to move my old numbers to the service.

Not so easy. To cancel the transfer freeze I'd imposed ages ago when a shady long-distance provider hijacked my lines, I waited on hold for half an hour with Qwest. A couple of days later, the company mailed me two messages confirming service changes that I hadn't ordered. My final call to sort things out made me happy to be leaving.

Transfer Day brought a brief outage that required a call to T-Mobile. Then dial tones disappeared again, though rebooting the router again fixed things. But when I forwarded calls to my cell phone, some of them never made it there, and voice mail ended up in the wrong inbox. And my accountant sent me a frantic e-mail wondering why he was getting only a fast busy signal from my old phone number.

Counting the value of my time, switching to this service may end up being a dubious bargain. I have now spent several hours conferring with T-Mobile. A beta version of new router software was supposed to cure the reboot problem, but it happened again, and this time, voice mail did not pick up calls during the hang. That was fixed by a more recent beta, but other odd glitches persist.

As I write, this program is being test-marketed in Seattle (where I am) and in Dallas, so I've been what I usually try not to be--an early adopter.

But voice over IP and T-Mobile's network have both been around for years. How come most Net-based alternatives to the mature and reliable but overpriced landline phone system are still clever-seeming upstarts you can't quite count on?