The IEEE-488 Bus was one of many expansion slots at the rear of the Commodore PET computer. It was not much used, because exorbitant fees were charged to licence devices for it, compared to the PET's user and expansion ports.
it was originally developed and used on the LSI-11
computer, and, i am told by Gorgonzola, (Thanks!)
that it is the Standardized form of the HP-IB
bus.
IEEE-488 instrument interface bus pinout:
1
DIO1Data Line 1
2
DIO2Data Line 2
3
DIO3Data Line 3
4
DIO4Data line 4
5
EOIEnd of message
6
DAVData valid
7
NRFDNot Ready For Data
8
NDACNot Data ACcepted(?)
9
IFCInterFace Clear
10
SRQ(peripheral) Service ReQest
11
ATNATteNtion: data is command
12
SHIELDno connection
13
DIO5Data line 5
14
DIO6Data line 6
15
DIO7Data line 7
16
DIO8Data line 8
17
REN
18-24
GNDGrouND