Binary Synchronous Transmission has been largely replaced in

IBM environments with SDLC. Bisync was developed for

batch communications between a System 360 computer and the

IBM 2780 and 3780 Remote Job Entry (RJE) terminals. It

supports RJE and on-line terminals in the CICS/VSE

environment. It operates with EBCDIC or ASCII charactersets. It requires that every message be acknowledged (ACK)

or negatively acknowledged (NACK) so it has high

transmission overhead. It is typically character oriented and

half-duplex, although some of the bisync protocol flavours

or dialects support binary transmission and full-duplex

operation.