The Gpib Connector; Figure 3.2 - Gpib Connector - Newport LDC-3706 Series User Manual

The GPIB Connector

The standard GPIB connector consists of 16 signal lines in a 24-pin stackable connector. The extra
pins are used to make twisted pairs with several of the lines. There are eight data input/output lines,
three handshake lines, and five interface management lines.
Eight data I/O (DIO) lines carry both data (including device dependent commands) and interface
messages. The ATN interface management line determines whether these lines contain data or
interface messages.
Three handshake lines ensure that all data and messages are reliably transferred:
 NRFD (not ready for data) indicates whether a device can receive the next byte of data or
message.
 NDAC (not data accepted) indicates whether a receiving device has accepted a byte of
data or message.
 DAV (data valid) indicates that the signal levels on the data lines are stable and available
for the receiving device(s) to accept.
Five interface management lines control the flow of information:
 ATN (attention) is set by the controller in charge to define the I/O lines for data or
interface messages.
 IFC (interface clear) is set by the system controller to initialize the bus and assert itself as
controller in charge.
 REN (remote enable) is set by the controller to place addressed devices into remote or
local (front panel) control mode.
 SRQ (service request) can be set by any device in the system to request service from the
controller.

EOI (end or identify) is used by talkers to identify the end of a message.
December 2019
Figure 3.2 – GPIB Connector
43 LDC-3706 Series Laser Controller