Abstract: A computer system automatically senses characteristics of diverse peripheral devices connected to a common communications port, and automatically maximizes the communications speed with the devices. Coupled in daisy chain fashion to the communications port, all peripheral devices receive every signal issued from the controller port, each device responding only to signals addressed to that device or signals addressed to a universal address. The controller first receives an identifier from peripheral devices attached to the controller port. The controller then interprets the received identifiers to determine a maximum communications speed for each device. Next, the controller and the attached peripheral devices are configured to communicate at the maximum communications speed of the slowest device. This guarantees that all messages sent by the controller are compatible with all peripheral devices.