Test Head

There are a number of testers available that can automate the hard part of testing diagnostics. If the fault is identified quickly and accurately the operating costs can be reduced. Sending an engineer to the right place immediately reduces time and preventing un-necessary truck rolls saving money. Test Head Products

Distance: TDR

An acurate distance measurement from the central office (exchange) to the customers premises. This can be used to detect where the fault is along the circuit, it is especially helpful when used with a database that holds distances of cabinets or distribution points. It is also used to check if the line qualifies for Broadband or other services.

 

AC Voltage.

There should be no ac voltage on the line. People doing DIY extensions have been known to put 240V mains onto the circuit and items such as modems can fail and put weird voltages like 85V out on the pair.

 

DC Voltage.

Any dc voltage coming back from the line side is wrong and is likely to be from faulty equipment at the customers premises.

A DC voltage of 50V would be expected on the exchange side, a feature may include listening in for dial tone.

 

Earth A leg / B leg.

Earth on one of the legs is quite common, caused by your phone line pair making physical contact with another pair or simply to earth. Mainly caused by water pennetration, damp or badly made connections.

 

Loop or Short Circuit.

A "Loop" or short circuit is often caused by water penetration or damp getting into distribution boxes. Bad connections in junction boxes where exposed wires are touching or connecting with other wires in the cable.


Resistance.

The overall resistance in the circuit can affect the quality service and also indicate a fault. Resistance between the A and B legs of the pair can be affected by penetrating damp, water impairment, loose connections, distance etc. Some of these faults maybe intermittent and occur more when the weather is bad.

 

Capacitance.

The measured capacitance is relative to the cable type and cable length. Most Telecom companies will have a standard value per kilometre of cable. Capacitance is affected by the number of joints along the cable length, the number of splitters and filters in the customers premises and customer connected devices such as modems.