Phone

From TreoCentral

The Treo also acts like a phone. This is considered by many as the primary function of the device. Voice is captured as analog data and then later encapsulated into digital frames. These frames then are transmitted by a process which varies from technology to technology. In a nutshell, CDMA (Code Division Multiple Access) allocates a specific code to the signal. The code's interference properties are then used to carry out the multiplexing scheme. The commonly used terminology CDMA, TDMA, and FDMA all refer to multiplexing schemes, not modulation. TDMA (Time Division Multiple Access) basically allocates a slice of time to each device on a given frequency when they are allowed to transmit. FDMA (Frequency Division Multiple Access) basically creates subdivisions of frequencies and uses a control to make sure no two devices transmit on the same subdivision. This is almost like its CDMA counterpart, in that users are separated by frequency as opposed to time (TDMA).