NEC (D3)

Description

A digital encoding format developed by NEC America that supports tone only and numeric pages at a rate of 200bps. This format was developed for use in NEC R3-D3 pagers. This format uses 2 methods for preserving battery life. First a preamble is used to alert ALL pagers that there are incoming messages. Pagers remain idle till preamble detection. Second, pagers are grouped by address into 1 of 4 different groups. Each group is transmitted during a fixed time period and pagers only power up to look for its own address during the time its group is transmitted. Error correcting codes and even parity bits are used on each address and message.