Improved addressing for a multipoint communication system for patient monitoring

Abstract

Abstract 57 A method for dynamically assigning addresses to new modules as they are coupled to a communication system (100) 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 (102) in the display unit, with all modules acting as secondary stations (104, 106, 108). The primary station (102) periodically broadcasts a time-tag to all modules at a thirty-two hertz rate. At power up, each module obtains a number, modulo 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., two or more modules request an address at the same time), the primary SDLC controller detects a CRC error and ignores the SDLC frame. The modules will each time-out and obtain a new number, modulo 16, derived from the next significant four bits of the module serial number. This process continues until the module obtains an address. (Fig. 1) .

Inventors

• 👤 Glen R. Sherwood, Jr.
• 👤 James B. Moon
• 👤 Gordon A. Moyle

Bibliographic Details