需积分: 10 15 下载量 85 浏览量 2014-01-20 14:59:50 上传 评论 收藏 9.19MB DOCX 举报
GUIDE ON THE USE OF THE OVERVOLTAGE RESISTIBILITY RECOMMENDATIONS
GUIDE ON THE USE OF THE OVERVOLTAGE
The Resistibility Guide assists test laboratories in implementing the correct tests for ITU-T K.20, K.21, and
K.45 compliance testing. It will have four definitive sections:
1) introduction with general comments
2) definition of terms
3) general test plan flow charts
4) test circuit schematics
This guide will assist the lab engineers and technicians in developing the correct test plans for equipment
being submitted for ITU-T K.20, K.21 or K.45 compliance testing. It provides the proper sequence of testing
to be conducted, shows specific test sequence for single pair ports and multiple pair ports with and without
primary protection in both internal and external environments:
1) symmetric single pair ports,
2) coaxial ports,
3) power ports and
4) ac mains ports
This Guide also provides a practical example, using a Home Gateway application that is subject to
Recommendation ITU-T K.21. This application example contains ADSL port types, mains power port types,
FXO and FXS port types, Ethernet port types, and USB port types.
The testing of equipment, particularly equipment with multiple external and internal ports, is complex and
lengthy. There are many tests per port and many combinations of external and internal ports to test. These
tests are performed with combinations of ports terminated and coupled to earth. The purpose of this
document is assist in laying out a test plan to ensure that adequate testing is performed to ensure compliance
with the required recommendation.
The present document is composed of 3 parts:
General remarks, definitions
General test plan
Test plan according to the family of equipment.
This recommendation applies to all equipment covered by the scopes of Recommendations ITU-T K.20,
K.21 and K.45 recommendations.
3 Normative references
The following referenced documents are indispensable for the application of this document.
For dated references, only the edition cited applies. For undated references, the latest edition
of the referenced document (including any amendments) applies.
Recommendation ITU-T K.20, "Resistibility of telecommunication equipment installed in a
telecommunications centre to overvoltages and overcurrents".
- 2 -
Recommendation ITU-T K.21, "Resistibility of telecommunication equipment installed in customer premises
to overvoltages and overcurrents".
Recommendation ITU-T K.45"Resistibility of telecommunication equipment installed in the access and
trunk networks to overvoltages and overcurrents".
Recommendation ITU-T K.44, "Resistibility tests for telecommunication equipment exposed to overvoltages
and overcurrents – Basic Recommendation".
4 Terms, definitions and abbreviations
A consequent number of terms, definitions and abbreviations are used; consequently the operator shall refer
to Recommendation ITU-T K.44, §3.
5 Information required by the test laboratory
5.1 Required level of resistibility
Normally the level of resistibility would be specified by the manufacturer or the network operator. Guidance
on this choice is given in section 5/K.44.
5.2 Characteristics of the agreed primary protector
The characteristics of the “agreed primary protector” are needed to determine the characteristics of the
special test protector. Normally the agreed primary protector would be specified by the manufacturer or the
network operator. Guidance on a suitable primary protector is given in section 8.5/K.44.
5.3 Port classification (external or internal)
Normally the port type would be specified by the manufacturer as this is determined by the design and
intended use of the port. Guidance on determining the port type is given in section A.2.1/K.44.
5.4 Port types
The port types are specified in section 7.1/K.44. The manufacturer should define the boundaries of the
equipment and specify the port type of each port.
5.5 Test types
The test types are specified in section 7.2/K.44.
5.6 Test conditions
The test conditions are specified in section 7.3/K.44.
5.7 Test levels
The required test levels, to check compliance, are specified in corresponding tables of K.20, K.21 and K.45.
5.8 Test schematics
The schematics are given in Annex A/K.44.
Five groups of schematics are given in K.44 and these are:
- The generator schematics (Figures A.3-1 through A.3-6).
- The main schematics (Figures A.6.1-1 through A.6.7-4.).
- Connection of the decoupling element between the EUT and the associated equipment for the tested
port (Figures A.5-3 through A.5-9).
- 3 -
- Connection of the decoupling element and terminating elements for associated equipment (Figures
A.5-10 through A.5-16). These figures also show the coupling to ground elements for the untested
- Protection of the untested port (Figures A.5-7 through A.5-23).
Recommended coupling and decoupling elements are listed in Table A.5-1/K.44.
The required schematics are chosen knowing:
- The generator type,
- The type of tested port e.g. external symmetric pair,
- The types of terminated ports,
- The type of untested port coupled to earth.
- 4 -
6 Sequence of tests
Table 1 synthesizes the applicable tests for the external ports of equipment, with and without primary
protection. Tests for external multiple pairs/ ports are further elaborated in Table 2. It clearly shows the five
classes of tests, associated to each kind of port, depending on the presence or not of a primary protection
Table 1 – Applicable tests for an external single port
# ) *
- 5 -
6.1 Tests for an External single pair port
6.1.1 Without Primary Protection
22.214.171.124 Symmetric pair port
The four following flowcharts give the procedure to perform the tests relating to a symmetric pair port
- 我的内容管理 展开
- 我的资源 快来上传第一个资源
- 我的收益 登录查看自己的收益
- 我的积分 登录查看自己的积分
- 我的C币 登录后查看C币余额