Valhalla Scientific 4300C, Руководство по эксплуатации

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Bus Restrictions
The IEEE-488 Interfacing Standard (also known as IEC DTC66 (WG3), ANSI MC1-1, GPIB, HP-IB, etc.),
defines a bidirectional bus for interconnecting programmable instrumentation in a bit-parallel, byte-serial
fashion. It defines limitations as follows:
1. A maximum of 15 devices may be interconnected by a single bus.
2. The total bus length may not exceed 20 meters, with a maximum interconnection length of 4
meters.
3. Maximum transmission rate is 1 megabyte per second.
4. All bus data is digital.
Of the devices on the bus, only one may be the controller which exercises control over all other devices
and is also capable of operating as a talker or listener. The other devices may be listeners (only able to
receive data) or talkers (only able to send data), or both. The model 4300C can talk and listen. The
controller may address other devices and command them to listen or talk. Only one device may talk at
any one time.
The interconnecting cable consists of sixteen signal wires and eight ground returns linking devices into a
complete system:
Eight data wires (DIO-0 thru DIO-7)
Five management wires (ATN, EOI, SRQ, IFC, and REN)
Three "handshake" wires (DAV, NRFD and NDAC)
Each cable connector is a plug/socket combination to permit "daisy-chaining" of units. It should be noted
that these wires use "inverse logic". That is to say that a low level indicates the true (asserted) state, and
a high level indicates a false (non-asserted) state.