Twisted-Pair Cable, Wire Distances | Nikon XX152-02-00 manual

Twisted-Pair Cable

Caution: Careful selection of the proper cable is essential to obtain the best performance from this equipment. Vicon assumes no responsibility for poor performance when cables other than those recommended are installed.

Materials

Use a pure copper stranded or solid conductor with or without a tin plating to obtain a low DC resistance. Do not use cable with either steel or aluminum stranded conductor because these do not transfer signals effectively for long distances. The preferred insulation is Polyvinyl chloride (PVC). It has better electrical characteristics than polyethylene and resists flames, sunlight and most solvents, but is more vulnerable to moisture.

Cable Types

The most commonly used cable types are point-to-point unshielded twisted pair wire, stranded or solid, unjacketed, 24 gauge or thicker. They can be category 2, 3, 4, or 5. The video signal may co-exist in the same wire bundle as other video, telephone, data, control signals or low-voltage power. It is also acceptable to run the signal adjacent to fluorescent lights or other power sources (in accordance with National Electrical Code, local and other safety requirements). Make sure the pair of wires carrying the video signal is sent as a twisted pair (the blue-white/white-blue wires twisted together as a pair), not a “split pair” (blue-white conductor, part of one pair/orange-white conductor, part of another pair).

Choose a Belden or equivalent cable type by referring to the characteristics and maximum distances listed below. The characteristics of the cables in the Tables should be used as a guideline when cables other than Belden are used. Materials and construction must follow the guidelines above.

Wire resistance may be measured with an ohmmeter by shorting the two conductors together at the far end and measuring the loop-resistance out and back. Compare your readings to the following chart.

Wire Distances

Distance ft (m)			Wire Gauge AWG
Distance ft (m)		18	20	22	24
250	(76)	3Ω	5Ω	8Ω	13Ω
315	(96)	4Ω	6Ω	10Ω	16Ω
397 (121)		5Ω	8Ω	13Ω	21Ω
500 (152)		7Ω	10Ω	17Ω	26Ω
630 (192)		8Ω	13Ω	21Ω	33Ω
794 (242)		10Ω	16Ω	26Ω	41Ω
1000	(305)	13Ω	20Ω	33Ω	52Ω
1260	(384)	16Ω	25Ω	42Ω	66Ω
1587	(484)	21Ω	32Ω	52Ω	83Ω
2000	(610)	26Ω	40Ω	66Ω	104Ω

Note: All quoted distance specifications include any coaxial cable in the run. It is recommended that the wire distance be measured to ensure that the capability of the product is correct.

Recommended Unshielded Twisted-Pair Cable Type

Cable Type	Wire Size	Insulation Material	Conductor Type	Resistance (ohms)	Number of
	(AWG)				Twisted Pairs
Belden1721X	24, Solid	Polyethylene	Bare Copper	100	1

20 • Reference

XX152-02-00 Rev 1204 SurveyorVFT Fixed Camera Dome