Keithley 199 Instruction Manual page 185

APPENDIX C
Unaddress Commands
The two unaddress commands are used by the controller
to remwe any talkers or listeners from the bus. ATN is true
when these commands are asserted.
UNL &Jo&ten)-Listeners are placed in the listener idle
state by UNL.
LINT KJntalk)-Any previously commanded talkers will
be placed in the talker idle state by UNT.
Device-Dependent Commands
The purpose of de-vice-dependent cornman ds wiIl depend
on instroment configuration. Generally, these commands
are sent as one or more ASCII characters that command
the-device to perform a specific action. For example, the
command string ROX is used to control the measurement
range of the Model 199.
The IEEE488 bus treats these commands as data in that
ATN is false when the commands are transmitted.
Command Codes
Command codes for the various commands that use the
data lines are summarized in Figure C-3. Hexadecimal and
and decimal values for the various commands are listed
in Table C-2.
C-5