Signal Designations; Control/Signal Lines; Earth Conductor (Cables For Power Supply) - HEIDENHAIN TNC 415 Technical Manual

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):
DTR (Data Terminal Ready):
DSR (Data Set Ready):
RTS (Request to Send):
CTS (Clear to Send):

Earth conductor (cables for power supply):

Chassis GND:
Signal GND:
8-12 TNC 407/TNC 415/TNC 425
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.
This signal shows that the TNC is ready for service
(e.g. receiving buffer full => DTR = Low).
Peripheral ready for service.
Switch transmission unit on. TNC wishes to transmit
data.
Readiness for transmission. The peripheral is ready to
receive data.
Casing connection
0-Volt lines for all signals
2 TNC data interfaces 01.98