Cellular digital packet data

Cellular Digital Packet Data, CDPD uses unused bandwidth normally used by AMPS (analog) mobile phones between 800 and 900 MHz to transfer data. Speeds up to 19.2 kbit/s are possible.

As of the year 2004, major carriers in the USA are threatening to shut down CDPD service. AT&T will give out no new IP addresses. The threatened shutdown has been delayed several times (the service has a number of entrenched users and no easy direct replacement exists).

A link page about CDPD.