Measurement Computing Micro488/p - Manual (Page 13)

Getting Started 09-26-02 2-3
Micro/488p Serial Connection
Pin Signal Name I/O Function
2 RxD
Receive Data Input Accepts serial data sent by the RS-232 host.
The signal level is low true.
3 TxD
Transmit Data Output Transmits serial data to the RS-232 host.
The signal level is low true.
4 CTS
Clear To Send Input The CTS input is used as a hardware handshake
line to prevent the Micro488/p from transmitting
serial data when the RS-232 host is not ready to
accept it.
When RTS/CTS handshake is selected, the
Micro488/p will not transmit data out TxD while
this line is un-asserted (low).
If XON/XOFF handshake is selected, the CTS
line is not tested to determine if it can transmit
data.
5 RTS
Request To Send Output The RTS output is used as a hardware
handshake line to prevent the RS-232 host from
transmitting serial data if the Micro488/p is not
ready to accept it.
6 DSR
Data Set Ready Input This pin is used to provide power for the
Micro488/p if the DTR pin is in its false (LOW)
state, this pin must be in its true (HIGH) state in
order for the Micro488/p to operate properly.
7 Gnd
Ground N/A This pin sets the ground reference point for
the other RS-232 inputs and outputs.
8 DCD
Data Carrier Detect Output The function of this pin is similar to the CTS pin.
This pin is tied internally to its true (HIGH) state.
20 DTR
DataTerminal Ready Input Used to provide power for the Micro488/p when
the DSR pin (pin 6) is in its false (LOW) state.
Note that the DTR pin (pin 20) must be in its
true (HIGH) state in order for the Micro488/p to
operate properly.