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The IBM 2790 Data Communications System was a family of devices intended for "in-plant data communications and production monitoring." The 2790 consisted of the following components, all connected by a two-wire loop operating at 500 kbit/s: * The IBM 2715 transmission controller, which controlled the other system components. The 2715 could be attached directly to a System/360 multiplexor channel, to an IBM 1800 Data Acquisition and Control System, an IBM System/7, or to a 270x communications controller for remote host attachment. The 2715 could support up to 32 KB of magnetic core memory with a 1.2 μs cycle time, an internal disk for microcode load, a 2740 printer/keyboard, and a real time clock. * The IBM 2791 Area Station was a tabletop unit attached to the 2790 loop. The 2791 could read ten column identification badges and eighty column punched cards, and had a twelve key pad for direct entry of numeric data. The 2791 could attach up to thirty-two 2795/2796 data entry units, a 1053 printer, up to three 1035 remote badge readers, and an OEM device. The 2791 had nine user defined "transaction buttons". * The IBM 2793 Area Station was similar, but lacked the ability to accept input data directly. It could attach up to thirty-two data entry units and a 1053 printer. * The IBM 2795 and 2796 Data Entry Units "for reporting job and machine status and production information."〔 Both had two ten-position switches and a ten column badge reader. The 2796 had an additional two switches and allowed for manual entry of up to four digits. ==References== 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「IBM 2790」の詳細全文を読む スポンサード リンク
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