NEC Univerge sv8500 Manual page 2534

Calculating The Distance Between ATI Circuit Card and Modular Rosette
The distance M, in <Blue>, is determined according to the Direct-Current resistance of the power supply cables (–
48V and GND). Note that the maximum resistance is 26 Ω as shown in the following formulae:
≤
26 Ω
M = a + b + c
M: maximum Direct–Current resistance between the ATI circuit card and the Modular Rosette
a: Direct-Current resistance of the power supply cables (–48V and GND) in the range of A
b: Direct-Current resistance of the power supply cables (–48V and GND) in the range of B
c: Direct-Current resistance of the power supply cables (–48V and GND) in the range of C
Calculation Example
Calculate a, b and c using the following formulae:
You are not required to use cable lengths in meters. However, units of resistance that match the units of
Note:
length must be used. For example, if feet are used as units of length, DC resistance per foot must be used.
u (Ω/m)
a =
2
v (Ω/m)
b =
2
w (Ω/m)
c =
2
u: Direct-Current resistance per meter (
v: Direct-Current resistance per meter (
w: Direct-Current resistance per meter (
x: Cable length (m) in the range of A
y: Cable length (m) in the range of B
z: Cable length (m) in the range of C
Resistance of –48V cables
×
x (m) u (Ω/m)
+
Number of –48V cables
Resistance of –48V cables
×
y (m) v (Ω/m)
+
Number of –48V cables
Resistance of –48V cables
×
z (m) w (Ω/m)
+
Number of –48V cables
Ω /m) in the range of A
Ω
/m) in the range of B
Ω
/m) in the range of C
Resistance of GND cables
×
x (m)
1
Number of GND cable
Resistance of GND cables
×
y (m)
2
Number of GND cables
Resistance of GND cables
×
z (m)
2
Number of GND cables
VOL.3-47
CHAPTER 1 TERMINALS