National Instruments GPIB-120A ユーザーズマニュアル

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, devices can be linked in
either a linear configuration (shown in Figure A-2) or a star configuration (shown in
Figure A-3), or a combination of the two.

The standard connector is the Amphenol or Cinch Series 57 Microribbon or Amp Champ type.
An adapter cable using a non-standard cable and/or connector is used for special interconnecting
applications.

The GPIB uses negative logic with standard TTL logic levels.  When DAV is true, for example,
it is a TTL low level ( 

≤

 0.8 V), and when DAV is false, it is a TTL high level ( 

≥

 2.0 V).

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9

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24

DIO5

DIO6
DIO7
DIO8
REN
GND (TW PAIR W/DAV)
GND (TW PAIR W/NRFD)
GND (TW PAIR W/NDAC)
GND (TW PAIR W/IFC)
GND (TW PAIR W/SRQ)
GND (TW PAIR W/ATN)
SIGNAL GROUND

DIO1
DIO2
DIO3
DIO4

EOI

DAV

NRFD

NDAC

IFC

SRQ

ATN

SHIELD

Figure A-1.  GPIB Connector and the Signal Assignment