Cellular Digital Packet Data (
CDPD) was a wide-area mobile data service which used unused
bandwidth normally used by
AMPS mobile phones between 800 and 900 MHz to transfer data. Speeds up to 19.2 kbit/s were possible. The service was discontinued in conjunction with the retirement of the parent AMPS service; it has been functionally replaced by faster services such as
1xRTT,
EV-DO, and
UMTS/
HSPA.