A system and method for automatically and uniquely assigning identification codes to a plurality of slave processors. A master processor having communication port is linked to a first slave processor, which, itself, has first and second communication ports. The first communication port is used in support of the aforementioned link to the computer. A second slave processor, also having first and second serial ports, is linked by its first communication port to the second communication port of the first slave processor. The slave processors are programmed to read designated pins on their first communication ports. The read values determine the identification code of each processor. Thereafter, each slave processor outputs to its second port a value one greater than the value read from its first port. Therefore, each slave processor assigns itself a particular identification code and directs the next slave processor to assign itself an identification code one greater.