Measurement object
Horizontal link
In the horizontal link, most of the measured objects are cables, and most users choose "Permanent link", a small number of users choose "Channel" (Channel, also known as channel). The testing standards generally choose TIA568B, TIA568C, ISO11810 and GB50312-2007 standards.
The permanent link is the link from the socket of the user panel to the end of the socket of the distribution frame (note, including these two sockets), most users require the detection of the permanent link Road and file as acceptance report. Channel (channel) refers to the link from the crystal head on the computer network card to the crystal head of the switch port (note that these two crystal heads are not included). If a tested link meets the requirements of various parameters specified in the test standard, the parameter test of this link will be judged as "qualified".
Measurement system
Vertical link test/trunk subsystem
Usually refers to the optical cable and large pair in the trunk subsystem Most of the optical cables are multi-mode optical cables (based on system cost considerations), and the grade of large logarithmic cables generally does not exceed Category 5e (Cat5e). The fiber test level is mostly based on the first level test (ie loss attenuation/length test), and a small number of high-speed links (such as 10G/40G/100G) will be upgraded to the second level (ie loss test + high-resolution OTDR test judgment).
Backbone Link Test/Building Subsystem
In the backbone link, most of the tested objects are optical cables (single-mode/multi-mode). One object refers to the optical fiber between the building group (building group subsystem). The test of optical cable is mainly based on the first-level test (that is, the test attenuation/length), and a small number of users of high-speed applications will choose the second-level test.
Test method
The test implementation methods are divided into Party A test (implemented by Party A), Party B test (implemented by Party B), joint test by Party A and B (implemented by both parties), and third party Testing (entrust a third-party agency to implement testing). It is more common for Party A to commission Party B to conduct tests. The disadvantage is that the authenticity of test reports is often questioned. Therefore, the proportion of third-party testing is rising rapidly.
A small number of Party A will require a "selection test" to ensure the quality of the selected product; some Party B will also conduct a "selection test" and "entry test" for their suppliers. The entry test refers to the inspection test (incoming test) carried out when the goods enter the construction site or warehouse, so as to prevent "defective products" or counterfeit products from entering the wiring system.
The selection test and the approach test are the quality and compatibility testing of link components such as cables, jumpers, and modules. Test standards need "component standards" for testing. The most common mistake here is to use permanent link or channel test standards to conduct field test of cables and jumpers. Even if the quality of the components is unqualified, the test results are usually qualified. This erroneous testing method has a certain universality, which brings deep potential harm to Party A.
A small number of users (usually Party A) will require the "channel test" or "application test" to be done when the application is opened to ensure that the actual application is supported.
In the national standard GB50312, it is stipulated that the third-party sampling inspection pass rate must reach 99%, otherwise a full inspection is required.
For large-scale projects and data centers and other projects, in order to ensure their high quality and high reliability, it is recommended to conduct "selection test", "access test" and "permanent link test".
In principle, the link test report is a link-by-page report (A4 paper), with more than a dozen test parameters listed above. So a large-scale engineering optical test report with 20,000 points is more than 20,000 pages thick. Many projects have begun to switch to CD-ROM reports instead of paper reports, which are convenient for reference and statistics, and can reduce consumption, in line with the "green" trend.