Operation of the GPIB
Appendix E
GPIB-1014 User Manual
E-4
© National Instruments Corporation
Physical and Electrical Characteristics
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. This design allows devices to be linked in
either a linear or a star configuration, or a combination of the two. See Figures E-1, E-2, and E-3.
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 interconnection
applications.
The GPIB uses negative logic with standard TTL logic level. When DAV is true, for example, it is
a TTL low level (
≤
0.8V), and when DAV is false, it is a TTL high level (
≥
2.0V).
DIO1*
DIO2*
DIO3*
DIO4*
EOI*
DAV*
NRFD*
NDAC*
IFC*
SRQ*
ATN*
SHIELD
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
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
Figure E-1. The GPIB Connector and Signal Assignments