RCA ViSYS 25055RE1 Cordless extension handset - Black, silver -

Caller ID (CID)
The "called from" name and number that is transmitted and displayed over telephone lines. The caller has the ability to block delivery of this information by dialing 67 before dialing the destination number.

DECT (Digital Enhanced Cordless Telecommunications)
A digital wireless telephone technology that is expected to make cordless phones much more common in both businesses and homes in the future. Formerly called the Digital European Cordless Telecommunications standard because it was developed by European companies, DECT's present name reflects its global acceptance. Like another important wireless standard, Global System for Mobile communication (GSM), DECT uses time division multiple access (TDMA) to transmit radio signals to phones. Whereas GSM is optimized for mobile travel over large areas, DECT is designed especially for a smaller area with a large number of users, such as in cities and corporate complexes. A user can have a telephone equipped for both GSM and DECT (this is known as a dual-mode phone) and they can operate seamlessly.

Speakerphone
A phone that has a microphone and a speaker that allows you to talk to your caller without lifting the handset. This is best used in private offices and when multi party conferencing is required. Never use a speakerphone in a noisy environment.