4
Twisted pair cable specifications
The cables are an important part of an twisted pair installation and the overall performance and the
transmission distance depends on the selected twisted pair cable. Please note, that twisted pair
cable with stranded conductors are NOT suitable -
the conductors must be solid
.
Also note, that when shielded cables are used the transmission distance might be considerably
lowered, due to the higher capacitance introduced by the shield - carefully study the specification
on the actual cable and compare them with the table below. The choice between shielded and
unshielded cable will always be a compromise between the obtainable transmission distance and
immunity towards noise and crosstalk.
Description
Min.
Typ.
Max.
Unit
Solid conductors, diameter (Ø)
0,5
0,6-0,8
1
mm
Characteristic impedance @ <1 MHz
90
124
140
Ω
Capacitance
90
nF/km
Capacitance, unbalanced
800
pF/km
Inductance
0,7
mH/km
Isolation
500
M
Ω
Loop resistance
130
Ω
Attenuation @ approx. 5 MHz
30-36
dB/km
Twists
5
pcs./m
Examon suitable cables:ples
Mödinger A-2Y(L)2Y / 2x2x0,6 mm (2 pairs)
Alcatel 6806 Ecomatch (4 pairs)
Note:
When using cables including several pairs, not individually screened, it is, as a general rule,
not recommended to use more than one pair per cable in order to avoid possible crosstalk
phenomena.
Hint:
Avoid locating unscreened twisted pair cables parallel to data cables carrying high speed data
traffic, mains cables, or other cables with high energy and/or high frequency signals
Twisted pair video equipment Series 225
2800-00054
