A PCB that handles serial data exchange between the main controller, car operating panel, and floor indicators.
Full Definition
An elevator serial communication board (also termed a group controller communication card, CAN bus board, or serial I/O expander) is a printed circuit board that manages the serial data link between the main drive/controller unit and the distributed peripheral nodes — car operating panel (COP), landing call stations (LCS), floor position indicators, door controllers, and remote monitoring units. By serialising parallel I/O over a two- or four-wire bus (RS-485, CAN, LonWorks, or proprietary protocols), the serial communication board dramatically reduces the wiring harness running through the hoistway, replacing hundreds of travelling cable conductors with a single shielded twisted pair. Modern elevator serial buses employ differential signalling, cyclic redundancy checks (CRC), and watchdog supervision to ensure message integrity. A communication fault — lost bus arbitration, CRC error accumulation, or node dropout — is detected within one or two message cycles (typically < 100 ms) and results in a controlled stop. The board typically incorporates optical isolation between the bus and the controller logic to prevent ground loop interference. Firmware updates are applied by authorised technicians via USB or RS-232 service port. Boards must be stored in ESD-protected packaging; reverse polarity or static discharge can destroy bus transceivers permanently.
