scope:

This Standard specifies the electrical characteristics of the balanced voltage digital interface circuit, normally implemented in integrated circuit technology, that may be employed when specified for the interchange of serial binary signals between Data Terminal Equipment (DTE) and Data Circuit-Terminating Equipment (DCE) or in any point-to-point interconnection of serial binary signals between digital equipment.

This Standard is compatible with ITU-T (Formally CCITT) Recommendation V.11.

The interface circuit includes a generator connected by a balanced interconnecting cable to a load consisting of a receiver or receivers and a termination. The electrical characteristics of the circuit are specified in terms of required voltage, current, and resistance values obtained from direct measurements of the generator and receiver components at the interface points. The logic function of the generator and the receiver is not defined by this Standard, as it is application dependent. The receiver specification for the balanced interface is identical to that specified for the unbalanced interface circuit in TIA/EIA-423-B. Minimum performance requirements for the interconnecting cable are furnished. Guidance is given in Annex A.1 with respect to limitations on data signal rate imposed by the parameters of the cable length, balance, and termination, for individual installations.

The parameter values specified for the balanced generator and load components of the interface are designed such that balanced interface circuits may be used within the same interconnection as unbalanced interface circuits specified by TIA/EIA-423-B. For example, the balanced circuits may be used for data and timing while the unbalanced circuits may be used for low speed control functions.

It is intended that this Standard will be referenced by other standards that specify the complete DTE/DCE interface (e.g., connector, pin assignments, function) for applications where the electrical characteristics of a balanced voltage digital circuit are required. This Standard does not specify other characteristics of the DTE/DCE interface (such as signal quality and timing, etc.) essential for proper operation across the interface.

When this Standard is referenced by other standards or specifications, it should be noted that certain options are available. The preparer of those standards and specifications must determine and specify those optional features that are required for that application.