t is installed in a professional manner which capacitive and resistive tests can be performed from one end. will avoid sources of interference. For telephone line testing traditionally a 1 pair plus earth line test It would include statements such as: would be sufficient. It is becoming more common to test all 3 pairs in the line jack unit (LJU). There are a number of continuity, Cable runs to be more than 3.5m from fluorescent lamps, resistance and capacitance tests which can be performed to establish shredders and lift motors. the type and location of faults. 2. That they should not run in parallel and adjacent to power Table 33.6 shows some of the possible faults on pairs of wire, their cables and must cross at 90°. symptoms and whether capacitive (C) or resistive (R) tests are used 3. That the installation of the cable shall be such that noise to detect them. The distance to a short can be determined by the induced in the link should not exceed the following when resistance, given that the conductor resistance per metre is known. measured in accordance with IEEE 802.3i Section 14. Namely, The distance to an open circuit can be determined by the capacitance Impulse Noise above 264mV should not occur more frequently to earth between the pair. than one every 5 seconds; Crosstalk Noise should be below 4. That the wires are terminated in accordance with the IEE 803.3i Table 33.6 UTP fault systoms standard defining which colours are connected to each connec- tor pin. 33.6.2 Fault Earthing Test type Symptom Pair cross Works This is one area often overlooked by building cabling systems. Most Leg cross, split Capacitance imbalance, low equipment requires some earthing at the terminal, in the wiring mutual capacitance closet and at the equipment room. Where earthed socket outlets are provided on a structured cabling B leg to earth Works but attenuated signal system it is important that the adjacent socket earths are not con- and line permanently in nected together but wired back to their source. Socket outlet earths re