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Chapter 1
Interface Management Lines
Five GPIB hardware lines manage the flow of information across the bus.
Table 1-2 summarizes the GPIB interface management lines.
ATN (attention)
IFC (interface clear)
REN (remote enable)
SRQ (service request)
EOI (end or identify)
Setting Up and Configuring Your System
Devices are usually connected with a cable assembly consisting of a shielded
24-conductor cable with both a plug and receptacle connector at each end. With
this design, you can link devices in a linear configuration, a star configuration,
or a combination of the two. Figure 1-2 shows the linear and star
configurations.
© National Instruments Corp.
Table 1-2. GPIB Interface Management Lines
Line
NI-488.2M Software Description
Controller drives ATN true when it sends
commands and false when it sends data
messages.
System Controller drives the IFC line to
initialize the bus and make itself CIC.
System Controller drives the REN line to
place devices in remote or local program
mode.
Any device can drive the SRQ line to
asynchronously request service from the
Controller.
Talker uses the EOI line to mark the end of
a data message. Controller uses the EOI
line when it conducts a parallel poll.
1-7
NI-488.2M SRM for OS/2
Description
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