HEIDENHAIN TNC 335 Technical Manual - Manual (Page 517)

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TNC 360 2 TNC data interfaces 8/95
2 TNC data interfaces
2.1 General
The TNC 360 has a data interface, the RS-232-C/V.24. The HEIDENHAIN FE 401 floppy disk unit, ME
101 magnetic tape unit and external devices with appropriate data interfaces (computers, printers,
readers, punches) can be connected via the RS-232-C/V.24 interface.
Two transmission protocols are available for data transfer:
– Standard data transmission protocol
– Data transfer with Block Check Character (BCC)
The data format and control characters concerned are freely configurable within the framework of
this protocol.
2.2 RS-232-C/V.24 interface
RS-232-C is the designation of a serial interface based on the EIA standard of the same name and is
usable for transmission rates up to 19 200 bits/sec. Data transfer is executed asynchronously, with a
start bit before each character and one or two stop bits after each character. The interface is
designed for transmission distances of up to 20 meters.
The RS-232-C interface has been adopted with slight modifications and has been introduced into
Europe as the V.24 interface. The relevant German standard is DIN 66020.
2.2.1 Hardware
The physical connection between two RS-232-C/V.24 interfaces is an asymmetrical line, i.e. the
common ground connection between transmitter and receiver is used as a return wire.
Physical connections:
Sender
Transmitter
Übertragungsstrecke
Transmission path
Empfänger
Receiver
RxD TxD
RxD TxD