ELTEX TAU-36.IP - Page 281

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Universal Network Terminal TAU-72.IP/TAU-36.IP 281
Loop length is:
)(
20
km
R
R
L
Sp
Loop
Loop
=
4. In case of phone lines, loop resistance includes phone unit resistance: 600Ω
Equipment manufactured by Eltex provides maximum loop resistance of 3400Ω.
Subsequently, loop resistance excluding the phone unit equals to 2800Ω.
Thus, maximum loop length is calculated by the equation
)(
2800
20
km
R
L
Sp
Loop
=
Line length is calculated by the equation:
)(
1400
2
2800
2
2020
km
RR
L
LL
SpSp
Loop
CabLine
=

===
5. If you have to consider the cable temperature, the cable line length will be calculated with an
adjustment:
)(
))20(1(
1400
20
km
TaR
L
Sp
Line
−−
=
where:
a is a temperature factor (table value);
T-cable temperature.