The Professional Portable Radio Interface Option Board is a Rotronix Ltd proprietary Printed Circuit Board (PCB) with embedded in the memory of the microprocessor the proprietary software needed to utilize the Motorolaâ„¢ Professional Radio Option Interface (PROIS) software. The option board has a 9-pin D-shell connector to control the radio, e.g. transmit/receive, channel-change and feedback about channel status e.g. the radio is receiving a valid signal. The option board is connected to the radio via the 40-pin ZIF connector in the radio.