RS-232 Interface
28
X
mission Flow Control
(XO/XF)
Device Dependent Commands
The device-dependent commands used by the 4421 Power Meter are listed in
Table
16
, organized by category.
Table 16
RS-232 Device Dependent Command Summary
Function
Enables or disables the XON/XOFF flow control.
XO enables flow control.
XF disables flow control.
Remarks
When data is being sent from the power meter to the computer and flow control is
enabled, data transmission will be suspended when the XOFF character (hexadecimal
13) is sent by the computer. Transmission will resume when XON (hex 11) is sent by the
computer.
When data is being sent from the computer to the power meter, XOFF will be sent to
the computer when the input buffer fills up. XON will be sent to the computer when the
buffer has emptied.
Category
Command
Description
Measurement
FC
Forward carrier wave
FD
Forward dBm
RC
Reflected carrier wave
RD
Reflected dBm
SW
Standing wave ratio
RL
Return loss
MN
Minimum value
MX
Maximum value
Range
RYY
Auto range on
R00 to R17
Manual ranges
RNN
Auto range off, stay at present range
Terminators
YT
Two terminators: CR, LF
YO
One terminator: CR
YN
No terminator
Prefixes
PY
Prefix YES
PN
Prefix NO
Triggers
T0
Continuous on ENT
T1
One shot on ENT
T3
One shot on TRG
T5
One shot on measurement command
Status
U0
Send back current machine state
U1
Send back error conditions
U2
Send back revision levels
Self-Test
J0
Run self-test
Writable Store
WXXXXXX
Place XXXXXX in RAM
