Parallel interfaces
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.


24 pin Amphenol male connector layout
24 pin Amphenol male connector
According to 2 reports in our database (2 positive and 0 negative) this pinout should be correct.

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