The 5.8GHz AT&T 5840 won't conflict with your Wi-Fi network--and it sounds great, too.

What's behind the frequency specs?
The number and types of obstructions between the handset and the base unit, as well as interference from baby monitors, microwaves, and other such devices, can have a significant impact on range. But here's what you can expect from the different frequencies.

900MHz: These $20 to $50 phones cover between 500 and 1,300 square feet--fine for a studio or a small home.

2.4GHz: You'll get a range of 2,200 square feet, so this is a better option for two-bedroom or larger houses and for talking from a deck or a backyard. But since these phones operate in the same frequency as Wi-Fi networks, the two tend to conflict. Prices start at $50 for a basic model and rise to $300 for a high-end expandable system.

5.8GHz: While the jury is still out on whether these phones perform well enough to justify their higher price tags, consider one if your nest is wireless. Compared with what you get from the 2.4GHz alternatives, call quality is generally better, but range is similar. You'll pay anywhere from $100 to as much as $400.

What's the difference between analog and digital?

	If you live in a multiroom home, get a phone that supports additional handsets. The impressive Panasonic KX-TG2730S can handle eight.

The three transmission types are analog, digital, and digital-spread spectrum (DSS), also known as spread-spectrum technology (SST). We recommend you stay far away from 900MHz phones because many still use analog signals, which are prone to excessive static; you'll find yourself changing channels frequently without hearing any appreciable difference. Digital models, on the other hand, encode your conversations into digital packets, dramatically improving call quality. Furthermore, DSS and SST phones transmit and receive a signal over multiple frequencies, so chances are you'll get a better-sounding and more-secure chat.

What's the deal with changing channels?
If you're hearing a lot of static while talking to Grandma, try another channel. The more channels your phone has, the better. Look for autochannel search, a function that automatically finds the next free channel when static threatens a call in progress. Basic 900MHz phones have 20 to 60 channels, while 2.4GHz models offer 50 to 100.

Do I need more than one handset?
Do you sprint to the phone and answer breathlessly on the last ring? Do you miss calls because you can't find the blasted handset, which you realize later is wedged between the couch cushions? Does your significant other hog the line? If any of those scenarios sounds familiar, you're an excellent candidate for an expandable cordless system.

Several 2.4GHz and 5.8GHz options currently on the market let you add more handsets to the base. Some limit you to just one extra, while others can support up to 10 on a single jack. Along with the usual chatting functions, you'll get paging and teleconferencing, too.

	The cell phone-like Siemens SL3501 is brimming with extras, not the least of which is a 200-name phone book.

What else should I look for?
Cordless phones may not have the cool color screens and funky ring tones of mobiles, but be on the lookout for these options, especially the built-in speakerphone.

Answering machine: If you don't want to subscribe to voicemail service through your phone company, an integrated digital answering machine is essential. You'll want at least 10 to 15 minutes of recording time.

Built-in speakerphone: Once you've experienced this feature, it's hard to go without. The speakerphone is in the base, and higher-end models have one in each handset, as well. Almost all cordless phones can take a headset, but it usually isn't included in the box.

Caller ID: Not every phone supports caller ID, which local phone companies offer for around $5 per month. Read the box carefully.

Phone book: Cordless phones can't hold nearly as many names and numbers as mobiles, but some nicer models let you store upwards of 50. At the higher end, capacity increases to up to 100 entries.