System, methods and apparatus are described that offer improved performance of a serial bus used for Inter-Integrated Circuit (I2C) and/or camera control interface (CCI) operations. CCI extension (CCIe) devices are described. CCIe devices may be configured as a bus master or as a slave. In one method, a CCIe transmitter may generate a transition number from a set of bits, convert the transition number into a sequence of symbols, and transmit the sequence of symbols in the signaling state of a two-wire serial bus. Timing information may be encoded in the transitions between symbols of consecutive pairs of symbols in the sequence of symbols. For example, each transition may cause a change in the signaling state of at least one wire of the two-wire serial bus. A CCIe receiver may derive a receive clock from the transitions in order to receive and decode the sequence of symbols.