(1) (
Primary 
Domain 
Controller)  A service in a Windows server that manages security for its local domain.  Every domain has one PDC, which contains a database of usernames, passwords and permissions.  The PDC also provides a time service for the network and typically obtains the time from an edge router, which gets its time from the Internet.  See 
domain-based network and 
BDC.
(2) (
Personal 
Digital 
Communications)  A digital cellular phone system widely used in Japan.  Based on TDMA, it transmits in the 810-826 MHz and 1477-1501 MHz bands.  PDC is a 2G wireless system.  See 
cellular generations and 
PHS.