IBM 1050 -'Z_ -- --- IBM 1070 IBM 2740 or 2741 IBM System/360 Figure 2. Data Communication Units Attachable to the 2703 6 IBM 2780 IBM 1130 IBM : Channel l System/360 L __________ .1 Common Carrier TWX Terminals (Model 33/35 Type) I
character. Character buffering of up to four bytes is accomplished within the 2703 unit for start/stop type communications, while eight bytes can be buffered for synchronous (BSC) operations. When communi cating with the channel, the 2703 operates in multiple byte multiplex mode to request or transfer a short burst of up to four bytes each time a line requires service. On both input and output operations with the channel, any message buffering is performed by the processing unit. The 2703 does not impose restric tions on message length. All necessary bit-byte con versions, data control, and matching to common carrier equipment is accomplished in the transmis sion control unit. 6.1