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2 pin assignment – Metrohm 784 KFP Titrino User Manual

Page 98

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3.3 Properties of the RS 232 Interface

784 KFP Titrino

93

3.3.2 Pin Assignment


RS232C Interface


Transmitted Data (TxD).
If no data are transmitted, the line is held in the “ON” condition. Data
will only be sent when CTS is in the ”ON” condition.



Received Data (RxD)





Request to Send (RTS)
ON condition: Titrino is ready to send data.



Clear to Send (CTS)
ON condition: Remote station is ready to receive data.



Signal ground (GND)





Data Terminal Ready (DTR)
ON condition: Instrument is ready to receive data.

Protective earthing
Direct connection from cable plug to the protective ground of the instrument.

Polarity allocation of the signals
- Data lines (TxD, RxD)
voltage negative (<-3 V): signal state ”ON”
voltage positive (>+3 V): signal state ”ZERO”
- control or message lines (CTS, RTS, DTR)
voltage negative (<-3 V): OFF state
voltage positive (>+3 V): ON state
In the transitional range from +3 V to -3 V the signal state is undefined.

Driver 14C88

according to EIA RS 232C specification

Receiver 14C89

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Pin 4

Data Terminal Ready

Pin 5

Signal Ground

Pin 8

Clear To Send

Pin 7

Request To Send

Pin 2

Received Data

Pin 3

Transmitted Data