HEIDENHAIN SHB Data Interfaces for HEIDENHAIN - Manual (Page 8)

June 2011 2 – 9
2.2 RS-422/V.11 Interface
As the features of the V.24/RS-232-C interface are limited, the V.11/RS-422 interface was
developed. This interface is also standardized, but operates symmetrically.
The RS-422/V.11 serial interface is suitable for data transfer rates up to 10 Mbps.
At a baud rate of 38,400 bauds, data can be transferred over 1 km cable.
2.2.1 Hardware
The V.11/RS-422 standard operates with differential voltages. This offers the advantage that
interferences act on both signal lines equally and simultaneously over the transmission distance.
As the receiver only evaluates the differential voltages of the two signal lines, interferences are
not relevant. By this means, considerably longer lines can be installed, and the transfer rate is
much higher, as interferences are limited.
Physical connections: