System, methods and apparatus are described that include a serial bus, including a serial bus used for Inter-Integrated Circuit (I2C) and/or camera control interface (CCI) operations. The bus has a first line and a second line, a first set of devices coupled to the bus and a second set of devices coupled to the bus. A method of operating the bus includes configuring the first set of devices to use the first line for data transmissions and use the second line for a first clock signal in a first mode of operation, and configuring the second set of devices to use both the first line and the second line for data transmissions while embedding a second clock signal within symbol transitions of the data transmissions in a second mode of operation.