Metrohm 840 PC Control 5.0 / Touch Control - Manual (Page 322)

6.3 RS-232/USB Box
310
PC Control / Touch Control
6.3.2 RS-232 pin occupancy
RS-232 connection: D-sub 9-pole, male, full
Fig. 6.4: View of the RS-232 connections on the RS-232/USB Box
Pin 1: -
Pin 2: RxD
Data reception (Receive Data)
Pin 3: TxD Data transmission (Transmit Data)
Pin 4: DTR Ready to receive (Data Terminal Ready)
Pin 5: GND ⊥ Zero voltage, reference potential (ground)
Pin 6: DSR Only used for diagnosis (Data Set Ready)
Pin 7: RTS Transmitter to send (Request To Send)
Pin 8: CTS Receiver ready to receive (Clear To Send)
Pin 9: -