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Remote Operation via RS-232 Interface
Table 2-4. RS-232 Connector Pin Assignments
Pin No.
Signal Name and Description
1
Shield: Connected to the HP 3325B chassis.
2
BA orTXD (transmit data): Bit-serial data transmitted from the HP 3325B.
3
BB or RXD (receive data): Bit-serial data received by the HP 3325B.
4
CA or RTS (request to send): An output from the HP 3325B that is usually +1OV.
If hardware handshaking is enabled, this signal changes to -10V when the
HP 3325B buffer has room for less than 128 characters.
7
AB or Signal Ground: The reference potential for other signals.
Note: to
prevent ground loops, the HP 3325B RS-232 interface circuits
are Isolated from eaitj ground and from signal ground.
20
CD or DTR (data terminal ready): An output from the HP 3325B that Is usually
+10V. If hardware handshaking is enabled, this signal changes to -10V when
the HP 3325B buffer has room for less than 128 characters.
No other pins are connected.
The Cable
A standard printer cable should be used to connect the HP 3325B to another DTE device
such as a computer or terminal. The printer cable switches the receive and send connections,
as IS necessary when a DTE device is connected to another DTE device. Use an HP 13242G
to connect the
3325B to a controller with a 25-pin connector. Use an HP 24542G to
connect to a 9-pin male connector as may be found on a serial interface in a desktop
computer. Use an HP 92221P to connect to a 9-pin female connector as may be found on HP
Series 9000/300 computers.
A standard modem cable should be used to connect the HP 3325B to a modem (HP 13242N).
2-12
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