JDC

JDC stands for Japan Digital Cellular.  This was a TDMA system used in Japan that was one of Japan's first digital cellular networks.  The system is a time division multiplex system in some ways therefore similar to GSM or iDEN.  However, the JDC system had 3 cellular conversations sharing a single frequency instead of 8 cellular conversations per frequency as GSM and iDEN do.

Japan later called this system PDC - for Personal Digital Cellular - in the hopes that the standard would be used more internationally also outside Japan.  However, we are unaware that the system in fact had cellular usage outside Japan.