Abstract: A method for dynamically assigning addresses to new modules as they are coupled to a communication system with a synchronous data link control (SDLC) bus is described. These modules communicate with a display unit via the SDLC bus. The SDLC bus is controlled by a primary station in the display unit, with all modules acting as secondary stations. The primary station periodically broadcasts a time-tag to all modules at a thirty-two hertz rate. At power up, each module obtains a number, module 16, derived from the lower four bits of its unique twenty-four bit serial number. The module uses this number as a count of the number of time-tags which must occur before the module responds to the primary with an address request. If there are no collisions with other modules, the primary sends the module a packet which assigns the module the next available address. In the event of a collision (i.e.