Metrohm 788 IC Filtration Sample Processor - Manual (Page 139)

5.2 RS232 interface
788 IC Filtration Sample Processor
131
5.2.9 Pin assignment
RS232C interface external
Transmitted Data (TxD)
If no data transmission takes place, the line is maintained in
the ”ON” condition. Data are sent only when CTS and DSR are
in the ”ON” condition and DCD is in the ”OFF” condition.
Received Data (RxD)
Data are received only when DCD is ”ON”.
Request to Send (RTS)
ON condition: 788 IC Filtration Sample Processor is ready to
send data.
Clear to Send (CTS)
ON condition: Remote station is ready to receive data.
Data Set Ready (DSR)
ON condition: The transmission line is connected.
Signal Ground (GND)
Data Carrier Detect (DCD)
ON condition: The received signal level is within the tolerance
range (remote station is ready to send data).
Data Terminal Ready (DTR)
ON condition: 788 IC Filtration Sample Processor is ready to
receive data.
Pin 2
Transmitted Data
Pin 3
Received Data
Pin 4
Request to Send
Pin 5
Clear to Send
Pin 6
Data Set Ready
Pin 7
Signal Ground
Pin 8
Data Carrier Detect
Pin 20
Data Terminal Ready
Protective earth
Direct connection from cable connector to protective earth of
the device.
Polarity assignment of the signals
x Data lines (TxD, RxD)
Voltage negative (<–3 V): signal status ”ONE”
Voltage positive (>+3 V): signal status ”ZERO”
x Control or message lines (CTS, DSR, DCD, RTS, DTR)
Voltage negative (<–3 V): OFF status
Voltage positive (>+3 V): ON status
In the transition region from +3 V to –3 V, the signal status is
undefined.
Driver 14C88 to EIA RS 232C specification
Receiver 14C89 to EIA RS 232C specification
Contact arrangement at the socket
"RS 232" (male)
1 13
14 25
Connection cables to external devices must
have an appropriate 25-pin connector (female).
Metrohm offers connector sockets (K.210.9004)
and the associated housing (K.210.0001) as an
option for the preparation of such cables.
No liability whatsoever will be accepted for damage arising from the improper connection of devices.