Just kind of an FYI, while I2C uses a serial protocol, when the term "serial" is used for a device interface, people usually mean asynchronous serial which uses 2 wires, one for transmitting and one for receiving and are configured using baud rates and start and stop bits.
This type of interface is for communication between 2 devices.
IC2 also uses two wires, one for clock and a bidirectional data line. It is actually a bus.
A single master device can communicate (transmit and receive) with many (100+) slave devices.
---bill