JULABO LC 4 Temperature controller - Manual (Page 30)

Electrical connections
30
RS232C serial interface
This port can be used to connect a computer with an RS232C
cable for remote control of the controller.
9 6
5 1
RS232C
RS232 serial interface
This port can be used to connect a computer with an RS232 cable
for remote control of the circulator.
Pin assignments RS232:
Pin 2 RxD Receive Data
Pin 3 TxD Transmit Data
Pin 5 0 V Signal GND
Pin 7 RTS Request to send
Pin 8 CTS Clear to send
Pin 1; 4; 6, 9 Reserved - do not use!
RS232 interface cable
Circulator (9-pol) PC (9-pol)
Pin 2 RxD  Pin 3 TxD
Pin 3 TxD  Pin 2 RxD
Pin 5 GND  Pin 5 GND
Pin 7 RTS  Pin 8 CTS
Pin 8 CTS  Pin 7 RTS
Accessories: Order No. Description
8 980 073 RS232 interface cable 9-pol./9-pol. , 2,5 m
8 900 110 USB interface adapter cable