Electrical Contracting News (ECN) February 2017 | Page 36

SPECIAL FEATURE

SPECIAL FEATURE

TEST & MEASUREMENT
gap between a cable verifier and network troubleshooter with functionality that allows technicians to make quick work of testing for cable faults amongst live network drops .
The VDV II Pro can be connected to virtually any port and it will provide the user with a considerable amount of information , even when connection status at the other end of the cable is unknown .
When used in the work area it can be plugged into any RJ type outlet to identify the status of that port . If connected to an ethernet switch the VDV II Pro will identify the maximum speed of the switch from 10 to 1,000Mbps . Additionally , if PoE is in use , the tester will display the voltage available at the port and which pairs are supplying power .
Should the port be for telephone service , the VDV II Pro will identify whether an analog or digital service is detected and in the event an unrecognised service is detected , it will display the voltage present on each pair .
Problem solving for tracing live network cables
A common problem faced by users of simple cable verifiers is tracing a live network cable from the work area back to the network switch . A tone generator / probe cannot be effectively used on live network circuits , but a tester with port blink ( often called hub blink ) can be left connected to the outlet where it will slowly , repeatedly connect and disconnect until turned off . This will cause
the corresponding link LED at the network switch to blink in a slow , steady pattern which is easy to discern from the quick random flashing of the other LEDs in the equipment room . This feature saves untold time and frustration versus attempting to locate live circuits with a tone and probe .
Testing network devices with a cable verifier
Another little known trick is using an advanced cable verifier to test network devices , such as computers , IP phones and cameras . The VDV II Pro can be used to perform some basic network diagnostics to quickly rule out sections of the LAN when troubleshooting . Should a device like a computer fail to connect to the network the tester can be connected to the network outlet to check for service . This is not a novel idea , it ’ s one of the key uses of an advanced cable tester .
The VDV II Pro can also be connected directly to the computer ’ s network port to check its status . If working properly , the tester will display the advertised network speeds of the computer . If no ethernet signal is detected , it can be assumed that the network port on the computer or other device has failed . However , we can also check for incompatible network settings . For example , if the VDV II Pro displayed only 1,000Mbps instead of 10 / 100 / 1000 when connected to the network wall outlet , this would mean that the port on the switch is
A good cable verifier can provide many essential network troubleshooting functions at a fraction of the cost of a dedicated network troubleshooter .
set to fixed rather than auto-negotiation speed . Therefore , it will not connect , until the corresponding network device has been set to a compatible speed .
This type of diagnostic testing usually falls into the domain of network troubleshooting testers . However , a good cable verifier can provide many essential network troubleshooting functions at a fraction of the cost of a dedicated network troubleshooter .
When shopping for testers for wiremap and cable verification , one should also consider whether their work environment may include locations where there is an active ethernet LAN . Opting for a tester that can navigate both types of worksites can prevent the problems , and loss of time , encountered when an installer realises that a simple blink box or cable verifier offers no guidance when connected to live network circuits .

Smarter testing with the Eurotest Combo is now within your grasp

A 17 th Edition tester with a difference
• Handheld ( left or right )
• Red and green pass / fail LED indicators
• Help screens built-in for referencing on site
• Built-in line / loop impedance tables for automatic evaluation against current regulations
• Automated RCD testing to reduce test time
• Trip lock function to test loop impedance without tripping the RCD
• Bluetooth and memory download ( MI 3125BT )
• Quick , efficient and automatic R1 + R2 testing with A1214 Easiswitch ( MI 3125BT )
MI 3125BT Eurotest Combo BT MI 3125 Eurotest Combo LITE
A 1214 EASI switch
Metrel UK Phone : 01924 245000 E mail : info @ metrel . co . uk Web : www . metrel . co . uk