This Standard is applicable to the exchange of serial binary data signals and timing signals across the interface between Data Terminal Equipment (DTE) and synchronous Data Circuit-terminating Equipment (DCE). The DCE is considered to be synchronous if the timing signal circuits are required at the transmitting terminal or the receiving terminal, or both. The signal quality requirement is limited to synchronous transmission at the interface with synchronous DCEs. Signal quality pertaining to asynchronous DTEs is not part of this Standard. 

The interfaces referred to in this Standard conform to TIA/EIA standards:

TIA/EIA-232-F TIA/EIA-530-A together with TIA/EIA-422-B electrical characteristics

TIA/EIA-687 together with TIA/EIA-423-B electrical characteristics 

TIA/EIA-723 together with TIA/EIA-694 electrical characteristics 

This Standard specifies signal quality in relation to jitter, duty cycle, and frequency accuracy of timing signals and time displacement between data signals and timing signals. Electrical specifications for the signals are not part of this Standard but are part of the reference interface specifications. 

This Standard is of particular importance when the equipments in a system are furnished by different organizations. It does not attempt to indicate what action, if any, is to be taken if the limits are not met, but it is intended to provide a basis for agreement between the parties involved. 

This Standard does not describe any requirements for error performance for either a complete system or any system components. It should not be assumed that compliance with this Standard will produce error rates that are acceptable in any particular application. 

Any equipment which is represented as complying with this Standard shall meet the applicable specifications within the range of those factors which are described as appropriate for the normal operation of the equipment, such as primary power voltage and frequency, ambient temperature, or humidity. 

This Standard may also be used for DTE to DTE direct connections