RS-423

The standardized by the North American ANSI EIA -423 serial interface ( RS -423 also ), is an interface standard for a wired unbalanced serial data transmission. EIA -423 is specified in "Electrical Characteristics of Unbalanced Voltage Digital Interface Circuits ( ANSI/TIA/EIA-423-B-1996 ) ( R2001 ) ".

EIA -423 is similar to the EIA- 232 constructed. It complies with the international standard ITU-T X.26, which is identical with V.10. X.26 defines the electrical characteristics for unbalanced ( " unbalanced" ) lines at the interface between data terminal equipment (DTE ) and data communications equipment (DCE ). In contrast to the EIA -232 standard, in which a bi-directional point-to -point connection between two nodes is defined EIA -423, a unidirectional connection between a transmitter and to receivers 10.

Since the interface to EIA- 232 is ajar, the same restrictions apply. Due to the high voltage of the NRZ transmission of -3.6 ... -6V for logic 1 and 3.6 ... 6 V for logic 0, there is neither ( the wave resistance acc ) terminator is necessary. The transmission is unbalanced as EIA- 232 with respect to ground. As a receiver, however, instead of EIA- 232 is a differential receiver as with EIA-422 is used with its specific threshold of 200 mV.

A maximum cable length of 1200 m (corresponding to 4000 feet ) at 1 kbaud or 15 m at 100 kBaud is defined. This is slightly better than EIA -232, which originally stops at 20 Kbps due to the differential interpretation.

To minimize the crosstalk problem mentioned in EIA -232, EIA -423 at each data or Steuer-/Melde-Leitung has its own return line, similarly the EIA- 422. However, it is not true differential balanced ( balanced) transmission, since all return conductors have ground potential. Due to this fact, this standard has no distribution found for EIA-422 is much more immune to interference with the same effort.

The ITU -T Recommendation X.27 X.26 corresponds with the difference that the voltage levels "balanced ", ie symmetrically to the ground. It is identical to V.11.

General information about interfaces, parameters or characteristics is to be read in serial data transmission.