Loop testing in a fibre-to-the-kerb environment

The author discusses the problems raised by automated loop testing in a fibre-to-the-kerb system and attempts to justify the use of the linecard rather than a remotely located test-head for carrying out the tests. The reasons for the use of the linecard are as follows: almost all of the functionality required is already on the linecard, the incremental cost on this cost-sensitive component normally being nothing; the linecard, by definition, has a control path to the remotely located processor and, thereby, across the processor´s own control path, to the Element Manager, allowing tests to be executed on demand and routining information to be stored without the necessity of stealing additional bandwidth from the fibre; and routining can be carried out by the remotely-located processor since all it has to do is compare three previously-stored values for each line with those now measured, raising an alarm through its normal channel to the Element Manager if a change is noticed. This reduces the complexity of routining dramatically