PDC

PDC stands for Personal Digital Cellular.  This system is actually a rename of the first Japanese Cellular system called JDC - Japanese Digital Cellular.  Japan officials wished to rename JDC to PDC such that the standard might in fact be picked up by other countries in the world as well.  However, we are unaware that another country had picked up the PDC standard.  Perhaps the quick arrival of the next generation digital - CDMA - called CDMA One at times in Japan, may also have prevented more countries using PDC.

PDC is a version of cellular operating at about the 900 MHz and 1.5 GHz frequency bands.  It is a form of Time Division Multiplex cellular (TDMA) and therefore has some similarity not only to US TDMA but also GSM and Nextel's iDEN.  There are of course several differences even among the time division multiplex cellular systems.  The primary difference between PDC and GSM and iDEN is that PDC time shares three subscriber channels (3 conversations) per frequency slot, whereas GSM and iDEN time share 8 subscriber channels (8 conversations) per unique frequency.  The second variation is perhaps in terms of the second frequency band for each - the higher one.  PDC has a second frequency band in Japan at about 1.5 GHz, whereas GSM had a second frequency band also, but it was at 1.8 GHz.  Now of course, there is also some GSM, at least in the Americas, at 1.9 GHz also in the so-called PCS band.