Fluke Norma 4000 User Manual page 40

Remote Control
Users Guide
ATN
SRQ
REN
EOI
Handshake bus with 3 lines
DAV
NRFD (Not Ready For Data):
NDAC (Not Data Accepted):
3-4
Active LOW resets the interfaces of the instruments connected to the default
setting.
(Attention):
Active LOW signals the transmission of interface messages.
Inactive HIGH signals the transmission of device messages.
(Service Request):
Active LOW enables the instrument to send a service request to the controller.
(Remote Enable):
Active LOW enables switchover to remote control.
(End or Identify):
This has two functions in conjunction with ATN:
ATN = HIGH Active LOW marks the end of a data transmission.
ATN = LOW Active LOW triggers a parallel poll.
(Data Valid):
Active LOW signals a valid data byte on the data bus.
Active LOW signals that one of the devices connected is not ready to accept data.
Active LOW as long as the instrument is accepting the data present on the data
bus.