A communication system is provided, including a first master device to operate as a master of a communication according to a first protocol, a second master device to operate as a master of a communication according to a second protocol, a common slave device to operate as a slave of the communication according to the first protocol and the second protocol with respect to the first master device and the second master device, and a switch to control a connection between the common slave device and the first master device and between the common slave device and the second master device for a communication between the common slave device and one of the first master device to and the second master device. Thus, embodiments of the present invention provide a communication system that minimizes cost increases and improves communication speed in a system in which a plurality of master devices communicate with a slave device performing the same function as the master devices.