Remote Control - Fundamentals R&S NRP 
1144.1400.12 5.4  E-3 
Communication on Data Lines 
The IEC/IEEE bus is the most common remote interface for measuring devices. It has also been 
implemented in the R&S NRP. The remote controller and the R&S NRP communicate by means of 
messages. The messages sent on the data lines (Æ section "Interfaces", page 6.124) can be divided 
into two groups: 
 
•  Interface messages 
•  Device-dependent messages 
 
 
 
Interface Messages 
Interface messages are transmitted on the data lines of the IEC/IEEE bus when the ATN control line is 
active. Interface messages allow the controller and the device to communicate and can only be sent by 
a controller which serves as the IEC/IEEE-bus controller. Interface commands can be further classified 
as 
 
•  common commands 
•  addressed commands 
 
Common commands affect all devices connected to the IEC/IEEE bus without requiring an address, 
whereas addressed commands only affect devices addressed as a listener. The interface messages 
relevant for the device are described in the annex Æ "Interface Messages", page 6.127. 
 
 
 
Device-Dependent Messages (Commands and Responses) 
Device-dependent messages are transmitted on the data lines of the IEC/IEEE bus when the ATN 
control line is not active.  The ASCII code is used. Device-dependent messages are classified 
according to the direction in which they are sent: 
 
 
 
Commands 
are messages sent by the controller to the R&S NRP. They control the device functions and request 
information. The commands are classified 
 
according to the effect they have on the device:
 
 
Setting commands 
trigger device settings, e.g. an device reset or a configuration of 
the trigger system. 
Queries 
cause device data to be provided in the output queue, where they 
can be fetched via the IEC/IEEE bus. Queries are available for 
most of the setting commands. They are obtained by adding a 
question mark to the setting command.