A system and method for efficiently transferring data between devices. In various embodiments, a host computing device receives parallel data, encodes the parallel data as a count of pulses as serial data, and conveys the serial data to a peripheral device. The peripheral device decodes the received serial data to determine the parallel data, which is sent to processing logic. The devices send the encoded pluses on a bidirectional line, so the pulses are capable of being sent in both directions. The devices send the encoded pulses on the bidirectional line using a non-zero base voltage level. The devices are capable of using a voltage headroom when conveying encoded pulses between one another. Therefore, a full voltage swing between a ground reference voltage level and a power supply voltage level is not used when conveying the encoded pulses, which reduces power consumption.