3 signal designations – HEIDENHAIN TNC 407 (243 020) Technical Manual User Manual
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2.2.3 Signal designations
The RS-232-C/V.24 interface distinguishes between data lines, control/signal lines and the earth
conductor.
Data lines:
TxD
Transmitted data
RxD
Received data
Control/signal lines:
DCD (Data Carrier Detect):
Received signal level. The DCD signal indicates
to the transmitter that the information received
at the receiver lies within the defined level.
The DCD signal (pin 8) is not used by the TNC,
i.e. the TNC delivers no signal from pin 8.
DTR (Data Terminal Ready):
This signal shows that the TNC is ready for service
(e.g. receiving buffer full => DTR = Low).
DSR (Data Set Ready):
Peripheral ready for service.
RTS (Request to Send):
Switch transmission unit on. TNC wishes to transmit
data.
CTS (Clear to Send):
Readiness for transmission. The peripheral is ready to
receive data.
Earth conductor (cables for power supply):
Chassis GND:
Casing connection
Signal GND:
0-Volt lines for all signals