9
for example, 0.5 mm
2
. You are recommended to use dedicated shielded
audio cables, and the cable length is 100 meters (328.08 ft). Commonly
used audio cables include RCA audio cables and ordinary coaxial cables.
Alarm cables
Twisted pair cables are recommended. The wire gage of the insulated
core conductor should be in the range of 22 AWG to 28 AWG (24 and 26
AWG are recommended). The maximum DC impedance must not be
more than 100 ohm.
The following table shows the maximum length of alarm cables for wire
gages, taking 100 ohm as the benchmark.
Table 2-1
Maximum alarm cable length for different wire gages
Wire gage (AWG)
Maximum cable length
22
1453 m (4767.06 ft)
24
914 m (2998.69 ft)
26
570 m (1870.08 ft)
28
360 (1181.10 ft)
Network cables
Use twisted-pair cables. Currently, twisted pair cables include
unshielded twisted pair (UTP) and shielded twisted pair (STP). STP cables
are shielded with aluminum foil for radiation reduction purpose. STP
cables are more expensive than UTP cables, and they are harder to
install.
Ground wire
The length of the ground wire should be no more than 30 meters (98.43
ft), and its impedance must be less than 5 ohm. For more information,
see Standard YD5098.
