A communication system for communicating control data between a processor and an interface includes configuration registers, a packet processor, an interrupt processor, a timing monitor, a configuration sampler, a control-frame processor, a mode selector, and a transceiver. The processor, timing monitor, and configuration sampler generate control data, a timing signal and frame structure data, respectively. The packet processor generates a transmit control configuration packet, which includes the control data. The control-frame processor inserts the transmit control configuration packet into a first control frame, outputs the control frame to the interface and extracts a receive-configuration packet from a second control frame for generating one or more interrupts. The mode selector generates mode and idle signals for determining the mode of the interface, based on the idle signal. In one implementation, the system uses JESD control frames to reduce GPIO pin usage.