A bus adapter comprises: an interface unit configured to be connected to a Communication Module (CM), which is intended to communicated based on a first Communication Protocol (CP) such as CAN, via a first and a second signal lines, and to transceive bit signals through the first and the second signal lines; and a link control unit, connected to a data bus of a second CP, configured to transmit data stored in an outward buffer through the data bus, and to detect data from signals being carried on the data bus. The interface unit transmits data stored in an inward buffer to the CM via the second signal line in form of a format defined by the first CP and it drives the second signal line so that a bit string appears on the second signal line when the bit string is received through the first signal line.