Pinouts >  Parallel interfaces
24 pin Amphenol male connector layout
24 pin Amphenol male connector
The Hewlett-Packard Instrument Bus (HP-IB), implemented with name GPIB - General Purpose Instrumentation Bus by othe manufacturers, is a short-range digital communications standard developed by Hewlett-Packard (HP) for connecting electronic test and measurement devices (e.g. digital multimeters and logic analyzers) to controllers such as computers. The bus is still in use for this purpose.

IEEE-488 allows up to 15 devices to share a single bus by daisy-chaining. The maximum data rate is about one megabyte per second. The 16 signal lines within the passive interconnecting HP-IB cable are grouped into three clusters according to their functions: Data Bus, Data Byte Transfer Control Bus, and General Interface Management Bus.

Pin Name Description Source
1 DIO1 Data Bit 1 Talker
2 DIO2 Data Bit 2 Talker
3 DIO3 Data Bit 3 Talker
4 DIO4 Data Bit 4 Talker
5 EOI End Or Indentity Talker/Controller
6 DAV Data Valid Controller
7 NRFD Not Ready For Data Listener
8 NDAC No Data Accepted Listener
9 IFC Interface Clear Controller
10 SRQ Service Request Talker
11 ATN Attention Controller
12   Shield -
13 DIO5 Data Bit 5 Talker
14 DIO6 Data Bit 6 Talker
15 DIO7 Data Bit 7 Talker
16 DIO8 Data Bit 8 Talker
17 REN Remote Enabled Controller
18   Ground DAV -
19   Ground NRFD -
20   Ground NDAC -
21   Ground IFC -
22   Ground SRQ -
23   Ground ATN -
24   Logical Ground -

Data Lines:

Name Description
DIO1 to DIO8 Data Input Output

Handshake Lines:

Name Description
DAV Data Valid
NRFD Not Ready For Data
NDAC Not Data Accepted

Interface Management Lines:

Name Description
ATN Attention
IFC Interface Clear
REN Remote Enable
SRQ Service Request
EOI End or Identify

Some ancient computers used this bus widely: the Commodore PET/CBM range of educational/home/personal computers, whose disk drives, printers, modems, etc, were daisy-chain connected to the (host) computer, talking and listening on the designated bus lines to perform their jobs. All of Commodores post-PET/CBM 8-bit machines, from the VIC-20 to the C128, utilized a proprietary serial IEEE-488 for peripherals, with round DIN connectors instead of the heavy-duty HP-IB plugs. Several manufacturers used IEEE-488 as a peripheral interface to connect disk drives, tape drives, printers, plotters and advanced pocket calculators to their workstation products.


According to 2 reports in our database (2 positive and 0 negative) this pinout should be correct.

Is this pinout
Source(s) of this and additional information:,
Copyright © 2000-2021 by team, except user uploaded images.
No portion of this webpage may be reproduced in any form without visible link to .
Efforts have been made to ensure this page is correct, but it is the responsibility of the user to verify the data is correct for their application.