D-4
IEEE-488 Bus Overview
Model 6487 Reference Manual
Figure D-1
IEEE-488 bus configuration
Bus lines
The signal lines on the IEEE-488 bus are grouped into three different categories: data
lines, management lines, and handshake lines. The data lines handle bus data and com-
mands, while the management and handshake lines ensure that proper data transfer and
operation takes place. Each bus line is active low, with approximately zero volts represent-
ing a logic 1 (true). The following paragraphs describe the operation of these lines.
DEVICE 1
ABLE TO
TALK, LISTEN
AND CONTROL
(COMPUTER)
DEVICE 2
ABLE TO
TALK AND
LISTEN
2182
DEVICE 3
ONLY ABLE
TO LISTEN
(PRINTER)
DEVICE 4
ONLY ABLE
TO TALK
DAV
NRFD
NDAC
IFC
ATN
SRQ
REN
EOI
DATA BUS
DATA BYTE
TRANSFER
CONTROL
GENERAL
INTERFACE
MANAGEMENT
DIO 1–8 DATA
(8 LINES)
HANDSHAKE
BUS
MANAGEMENT
TO OTHER DEVICES
(6487)
