Patent ID: 8385907

Claim:
A communication system comprising: a communication device having a power management functionality and configured to connect with a communication line; and a phone device, the communication system configured to connect the communication device and the phone device with each other via wireless communication, wherein the communication device comprises: a wireless communication unit configured to wirelessly perform data communication and voice communication with an external device and the phone device; and a communication-device storage unit configured to store a communication-device network ID for identifying the communication device and a phone-device network ID for identifying the phone device, wherein the phone device comprises a phone-device storage unit configured to store the phone-device network ID and the communication-device network ID, wherein the communication system is configured to switch a communication state thereof from a first communication state, in which the wireless communication unit performs both data communication and voice communication with the external device and the phone device, to a second communication state, in which the data communication is performed between the phone device and the external device, by changing settings of the communication-device network ID and the phone device network ID stored in the communication-device storage unit and the phone-device storage unit in response to an electric power supply to the wireless communication unit being interrupted, wherein the first communication state is set when the communication-device network ID is used for the communication device, such that the communication device is identified as the communication device on the communication system, and the phone-device network ID is used for the phone device, such that the phone device is identified as the phone device on the communication system, and wherein the second communication state is set when the phone-device network ID is used for the communication device, such that the communication device is identified as the phone device on the communication system, and the communication-device network ID is used for the phone device, such that the phone device is identified as the communication device on the communication system.