1163.4 Communications ProtocolsThe BHT supports both the BHT-protocol and the BHT-Ir protocol for file transmission.3.4.1 BHT-protocol[ 1 ] OverviewThe BHT-protocol is the communications procedure used to transmit files between theBHT and a host (or between the BHTs). It adopts the response method using ACK/NAKcodes.The BHT-protocol is composed of a defined set of the control character sequencesincluding the following three phases:Phase 1: Establishment of data linkThe sending station confirms that the receiving station is ready toreceive data.Phase 2: Data transmissionThe sending station transmits data to the target receiving station.Phase 3: Release of data linkThe sending station confirms whether or not all of the transmitteddata has been correctly received by the receiving station. If yes, thesending station terminates the data transmission and releases thedata link.For details about the transmission control sequences and horizontal parity checking,refer to Appendix B, B.1, "BHT-protocol."
