Electronics Superstore:Buy a Cordless Telephone

Frequency: 900 MHz, 2.4 GHz, or 5.8 GHz
This is the radio frequency on which the phone transmits its signal. In general, the higher the frequency, the stronger the signal. The lowest, 900 MHz, is fine for household use, and 900 MHz models are very affordable, especially as manufacturers begin to phase them out.
'Uniden WXI377 900 MHz Water-Resistant Cordless Phone with Caller ID'

Phones using the 2.4 GHz band have a more energetic signal and usually offer more features, plus they're more likely to support multiple handsets. One downside is that many other electronic gadgets—from baby monitors to networking gear—may cause interference.
'Uniden DCT 648-2 2.4 GHz Expandable Cordless Phone with Dual Handsets, Answering System, and Caller ID'

Choosing the newer 5.8 GHz band alleviates this problem and improves the clarity, range, and possibly security—though 5.8 GHz models tend to cost more.
'Uniden TRU8866 5.8 GHz Digital Expandable 2-Line Cordless Speakerphone with Dual Keypads (Black)'

Transmission Type: Analog, Digital, or DSS
The most affordable and available option, analog, offers adequate voice quality and range—enough to carry on a conversation out in your yard. However, anyone with a radio scanner will be able to listen in, and transmission gets staticky when you're too far from the base station. No matter which frequency you choose, going digital offers a stronger, clearer signal and improved security but costs a little more. Digital spread spectrum (DSS) is a version of digital that distributes its signal across several frequencies. You'll pay more for DSS phones, but transmission is even clearer, stronger, and more secure.

Buying Advice
Our experience suggests that 900 MHz DSS offers excellent range for a low price and that 2.4 GHz models offer clear sound with great features. While operating on a band that's less trafficked than 2.4 GHz, 5.8 GHz phones cost more because of their more expensive chip sets.

Four Key Features
Here are the four most requested features built into cordless phones today.

+ Expandable Multi-handset Systems: More and more cordless phones are actually a self-contained phone network, comprising one base station that's connected to the phone jack and additional handsets (usually up to four or eight). The extra handsets require neither an extension cord from the base station nor a phone jack but only an electrical outlet. Note that dual-handset systems—those that come with two handsets in the box—usually cannot expand to accept more handsets; some can, however, so read the descriptions carefully.

+ Answering Devices: Combine your cordless phone (or phone system) with a digital answering device and avoid having one more gadget on your desk. Answering devices can feature remote access to retrieve messages when you're away from home, multiple mailboxes (a good choice for businesses or for a family with teenagers), and memo and conversation recording capabilities.

+ Caller ID/Call Waiting ID: If your phone supports caller ID, then the caller's name and phone number are displayed on your phone's LCD screen, eliminating the need for a caller ID box from the phone company. A variation of caller ID that's called "caller ID with call waiting" or "call waiting ID" displays information about a second (interrupting) call while you're already on the phone with someone else.

+ Speakerphones: Handy for meetings, conference calling, and long on-hold
times, many base units and some cordless handsets also function as a speakerphone. These systems also usually feature an intercom, letting you talk from the base to the handset. Some handsets work as intercoms, a handy feature for roping your phone into service as a baby/room monitor. Many speakerphones today use full duplex operation, in which your voice and your caller's voice are continuously transmitted in both directions to provide a natural conversational sound.