CDPD
Cellular Digital Packet Data: An industry standard for data transmission over cellular networks.
CDPD utilizes analogue cellular networks already in place in the United States and Canada to provide 2-way data communications for users of devices such as laptops and PDAs.
CDPD uses (currently unused) cellular channels (in the 800- to 900-MHz range) to transmit data in packets. This technology offers data transfer rates of up to 19.2kbps, quicker call set-up, and better error correction than using modems on an analogue cellular channel.