To network physical examination: Connectivity test of LAN link-surfing Network

Test twisted pair Cord jumper

Twisted pair jumpers are widely used in the connection of information sockets to computers, wiring racks to switches, connections between switches, connections between switches and routers, and connections between switches and fiber optic transceivers, so jumpers will directly affect the connectivity of network links.

You will need to test one end of the twisted pair into the "MAIN" port on the micro-scanner, the other end to the "loopback" port, or insert the wiring map connector. Press the "On/off" button to turn on the power switch. Press the "MODE" button until the word "Wiremap" appears on the LCD screen. The test results are displayed. The test results are digital, the line above shows the micro-scanner plug (that is, inserted in the main port) detected by the line, the following line shows the actual wiring situation.

Connected correctly

Figure 1 Normal connectivity display

As shown in Figure 1, there are instances where the connection is normal and there is no fault at all.

Connection error

Figure 2 Backward Alignment error display

When there is a failure, the word "FAULT" will appear on the LCD screen. As shown in Figure 2, "第3-6 pair" backward alignment failure, however, this jumper is called the intersection line, is used for the switch, hub common port cascade. As shown in Figure 3, "第4-5, 3-6 pair" crossover line failure, as shown in Figure 4, "第4-5, 3-6 pairs" of the separation of line failure.

Figure 3 Cross-snaplines error display

Circuit breakers and Short circuits

Figure 4 Separating the alignment error display

When the two ends of the line, that is, the circuit breaker, the line of the corresponding PIN digital LED will be blank, the LCD screen will display the word "Open" (as shown in Figure 5). When two lines are connected internally, short circuit, the number of pins corresponding to the short-circuit will be bracket, the LCD display "short" (as shown in Figure 6).

Figure 5 Circuit Breaker Error display

Link Overall test

Testing of the entire link is recommended when there is a problem with the connection between the computer and the switch. Unlike Test jumpers, the two-port test for Microscanner Pro cannot be plugged in at the same time because the entire link is far apart, so you must use the adapter and two RJ-45 jumpers to complete the test. Disconnect the jumper from the switch, connect to the adapter, and unplug the other end from the computer and connect to the tester. You can then test the connectivity of the link as you would a normal jumper.

Figure 6 Short-circuit error display

Wiring rack to Information outlet connection test

After network cabling is completed, if you want to test the connectivity of the wiring frame to the information socket to verify wiring quality, you must use the adapter and two RJ-45 jumpers to complete the test. The two jumpers are connected to the information outlet and the wiring frame to test the link, and then the test of the link can be realized according to the link overall test plan. It should be noted that two jumpers should be tested for connectivity prior to connectivity testing.

Test cable length

Whether it is Ethernet, Fast Ethernet or Gigabit Ethernet, the length of the line is clearly defined-the maximum length is 100 meters. So how do you determine if the cable that you have installed exceeds the specified length? Microscanner Pro uses TDR technology to obtain accurate length measurement results to make it easier to determine whether the cable length meets the standard.

1th step, insert the network cable. Plug one end of the twisted pair (or known length) into the "MAIN" port on the micro-scanner, and the other end is vacant.

The 2nd step is to calibrate the NVP value. NVP (nominal transmission speed) is the ratio of the speed of the signal to the speed of light in the cable, usually expressed as a percentage of the speed of light, NVP must be set up correctly to measure the length of the cable accurately.

Fig. 7 Calibration status of twisted pair tester

Enter the calibration status. Press the "On/off" button to turn off Microscanner Pro. Then, press the "MODE" button and press the "On/off" button to enter the calibration status (as shown in Figure 7). Once in the calibration state, the system defaults to the NVP value and the length of the cable are displayed on the LCD screen. The length of the cable at this time is calibrated by the stored nvp.

Set NVP. If you know the NVP of the cable you are using, you can use the ▲ or button to modify the value directly. At this point, the cable length is automatically recalculated according to the new set of NVP. If you insert a cable with a known length at this point in the Microscanner Pro port, you can also use the "▲" or "button to adjust the NVP value so that the measured cable length matches the known length to achieve the calibration NVP value.

In the calibration state, press the "MODE" button and the unit of length shown will switch between feet and meters. Once the required cable length or NVP has been displayed on the LCD screen, press the "On/off" button to end the "calibration" state and store the new calibration factor. Thereafter, Microscanner Pro will measure the length of the network cable with this factor until the next recalibration. It should be noted that the shortest cable used to calibrate the NVP value is not less than 15 m.

Fig. 8 Measuring the length of twisted-pair wire

The 3rd step is to measure the cable length. When you want to measure the end of the network cable into the "MAIN" port on the micro-scanner, press the "On/off" button to open Microscanner Pro, press the "MODE" button, until the LCD display "Length" of the word, the length of the network cable can be displayed (as shown in Figure 8). Press the "▲" or "" button to view the length of each pairing line separately.