HP 34401A User Manual page 151

Chapter 4 Remote Interface Reference
RS-232 Interface Configuration
DTR / DSR Handshake Protocol
The multimeter is configured as a
and uses the (Data Terminal Ready) and
DTR
of the -232 interface to handshake. The multimeter uses the
RS
to send a hold-off signal. The
multimeter will accept data from the interface. When the multimeter
sets the line
DTR FALSE
To disable the /
DTR DSR
the line to logic
DSR TRUE
also select a slower baud rate (300, 600, or 1200 baud) to ensure that
the data is transmitted correctly.
The multimeter sets the DTR line FALSE in the following cases:
1 When the multimeter's input buffer is full (when approximately
100 characters have been received), it sets the
the -232 connector). When enough characters have been removed to
RS
make space in the input buffer, the multimeter sets the
unless the second case (see below) prevents this.
2 When the multimeter wants to "talk" over the interface (which means
that it has processed a query) and has received a <new line> message
terminator, it will set the
query has been sent to the multimeter, the controller should read the
response before attempting to send more data. It also means that a
<new line> must terminate the command string. After the response has
been output, the multimeter sets the
first case (see above) prevents this.
The multimeter monitors the
is ready to accept data over the interface. The multimeter monitors the
line (pin 6 on the
DSR
The output is suspended if the
goes , transmission will resume.
TRUE
(Data Terminal Equipment) device
DTE
DSR
line must be
DTR
, the data must cease within 10 characters.
handshake, do not connect the
. If you disable the
DTR
line . This implies that once a
DTR FALSE
line
DTR
line to determine when the controller
DSR
-232 connector) before each character is sent.
RS
line is
DSR FALSE
(Data Set Ready) lines
line
DTR
before the
TRUE
line and tie
DTR
/ handshake,
DSR
line pin 4 on
DTR FALSE (
line ,
DTR TRUE
again, unless the
TRUE
. When the line
DSR
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