Operating instructions

Instrument Interfaces R&S ESCI
1166.6004.12 8.4 E-1
REN (Remote Enable),
active low permits the switch over to remote control.
EOI (End or Identify),
has two functions in connection with ATN:
active low marks the end of data transmission when ATN=high
active low triggers a parallel poll when ATN=low.
3. Handshake bus with three lines.
DAV (Data Valid),
active low signals a valid data byte on the data bus.
NRFD (Not Ready For Data),
active low signals that one of the devices connected is not ready for data transfer .
NDAC (Not Data Accepted),
active low as long as the device connected is accepting the data present on the data bus.
Interface Functions
Instruments which can be remote controlled via the IEC bus can be equipped with different interface
functions. Table 8-2 lists the interface functions appropriate for the instrument.
Table 8-2 Interface functions
Control character Interface function
SH1 Handshake source function (source handshake), full capability
AH1 Handshake sink function (acceptor handshake), full capability
L4 Listener function, full capability, unaddress if MTA.
T6 Talker function, full capability, ability to respond to serial poll, unaddress if MLA
SR1 Service request function (Service Request), full capability
PP1 Parallel poll function, full capability
RL1 Remote/Local switch over function, full capability
DC1 Reset function (Device Clear), full capability
DT1 Trigger function (Device Trigger), full capability
C0 No controller function
IEC Bus Messages
The messages transferred via the data lines of the IEC bus can be divided into two groups:
– interface messages and
– instrument messages.