scope:

This Recommendation provides the availability objective for radio-relay systems over a hypothetical reference digital path (HRDP) including the concept of unavailability of a HRDP and factors to be included in the assessment of unavailability. This Recommendation also provides the guidance of the availability and reliability of radio-relay systems.

It should be noted that this Recommendation could be used only for systems designed prior to the approval of Recommendation ITU-R F.1703 in 2005.

The reference to the hypothetical reference circuit (HRC) and related analogue information are removed in this revised version. For this information, see the previous version of this Recommendation, as well as the guide - List of ITU-R Recommendations on analogue systems in the fixed service in the frequency bands above 30 MHz (this document is available on the web page of ITU-R Working Party 5C), which contains a list of all the Recommendations referring to the analogue fixed service systems, including those already suppressed.