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INTERNATIONAL TELECOMMUNICATION UNION
ITU-T RECOMMENDATION SUMMARY
Rec. No. : K.28
Title : Characteristics of semi-conductor arrester assemblies for the
protection of telecommunications installations
Study Group : V - Protection against Electromagnetic Effects
Version : New
Date of adoption : 1991
Notes :
Careful survey of the electrical environment that telephone equipment
must safely survive, has led to the conclusion that semi-conductor
devices that are robust enough to act as primary protectors are now
possible. Semi-conductor devices provide for tightly toleranced and
stable over-voltage control, which does not change with age or
activity within their design capability. Furthermore, they introduce
negligible circuit noise on the circuits they are protecting.
Widespread trials of these semi-conductor overvoltage protectors for
primary protection are taking place and Recommendation K.28 provides
detailed guidance on the particular qualities which should be sought
when manufacturing or purchasing such devices. The trials and initial
applications are ongoing and some details of the technology may change
in the light of the results. Nevertheless, to bring the trials and
initial applications to the notice of a wider audience and to acquaint
potential users with both the advantages and disadvantages of these
devices, CCITT considers the subject to be important and stable
enough to publish a Recommendation on the new technology.
The purpose of Recommendation K.28 is to provide technical guidelines
for purchasers and manufacturers of semi-conductor arrester assemblies
(SAA) to ensure their satisfactory operation in the applications for
which they are intended.
It is intended to be used for the harmonization of specifications
issued by manufacturers of semi-conductor arrester assemblies (SAA)
and network operators.
Only minimum requirements are specified for essential characteristics.
As some users may be exposed to different environments or have
different operating conditions, service objectives or economic
constraints, the requirements of Recommendation K.28 may be modified
or further requirements added to suit local conditions. It is for
Administrations to classify the environment for a particular device,
taking into account business policy, and economic and technical
considerations.
To order the complete text of this Recommendation, please use the
Order Form for ITU-T Recommendations. An electronic version of this
form is available on ITUDOC (Winword 2.0: UPI=ITU-5265; ASCII: UPI=ITU-2488).