BS 6638-2:1989

This standard BS 6638-2:1989 Guide to transmission signal quality at DTE/DCE interfaces is classified in these ICS categories:

• 35.200 Interface and interconnection equipment

1.1 This International Standard specifies signal quality requirements for serial data transmission at the interface between synchronous transmission Data Terminal Equipment (DTE) and Data Circuit-terminating Equipment (DCE). The interface referred to in this International Standard conforms to CCITT Recommendations V.24 (telephone networks), X.24 (data networks) as specified in DCEs of CCITT Recommendations:

V.22, V.22bis, V.23, V.26. V.26bis, V.26ter, V.27, V.27bis, V.27ter, V.29, V.32, V.33, or

X.21bis together with V.28, electrical characteristics; or

V.35 together with V.28/V.35 electrical characteristics; or

V.36, V.37 or X.21 together with V.10/V.11, electrical characteristics; or

X.22 together with V.11, electrical characteristics.

It is also recognized and considered that during the evolution of ISDN there will exist V.-series and X.-series type interfaces at ISDN Reference point R, as specified in CCITT Recommendations V.110, X.30 and X.31.

The speed limitation is determined by the referenced CCITT DCE Recommendations in the X. (e.g. X.10) and V. (e.g. V.5, V.6) series.

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 International Standard.

1.2 This International Standard recognizes the need to have performance categories of signal quality depending on the type of interchange circuits used at the interface for signal element timing. Two classes of timing, codirectional timing and contradirectional timing, are considered.

The signal quality is categorized by measurements of timing displacement between data and timing signals, of jitter, duty cycle, and accuracy of the timing signals. Application to ISDN Reference point S/T is excluded.

1.3 This International Standard is of particular importance when the interconnected equipment is 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 parties involved.

1.4 This International Standard does not describe the signal quality of the DCE or the line associated with it. Neither does it describe any requirement for an acceptable bit error rate.

1.5 This International Standard may also be used for DTE to DTE direct connections when the referenced CCITT Interfaces are applied.

Signal quality requirements for serial data transmission.