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Bosch Security Systems | 04-2003 | 3922 988 43318 en
Digital Congress Network | Installation and Operating Manual | Chapter 10 - Installation Techniques
en | 10-8
Calculating the PCF of a System with respect to cable length
FIG 10-10 Graph for calculating the PCF value of a system including extension cable length
correction
10.4.2 Graph explanation
The Y-axis of the graph gives the PCF per trunk-outlet (max. 60 PCF) in relation to the X-axis, which
gives the length of extension cable used (max. 250 m (820 ft.)).
If the length of cable from the Trunk outlet exceeds 250 m (820 ft.), the graph shows that no units can
be connected. At 240 m (787 ft.), the graph shows that a PCF of 17 can be connected. For an
example of a single trunk-outlet limitation refer to FIG 10-11 and FIG 10-11.
For typical PCF graph references in relation to Trunk outlets and Tap-offs for systems with and without
extension cables refer to FIG 10-12.
FIG 10-11 Example Single Trunk-outlet limitations
Y
X
8020 40 60
100 120 140 160 180 200 220 240 250
5
10
15
20
17
25
30
35
40
45
50
55
60
0
54
60
49
60
54
48
42
36
44
38
33
6
11
16
22
27
6
12
18
24
30
7
13
20
27
33
40
47
53
60
8
15
22
30
37
45
52
60
9
17
26
34
43
51
60
9
18
28
37
46
55
10
20
30
40
50
60
11
22
33
44
55
12
24
36
48
60
14
27
41
54
15
30
45
17
60
60
Ext. Cable (m)
PCF value
Port 1
Rec.
Line
In
Out
In
Out
Symmetrical
Trunk
115 V-T4A 230 V -T2A
Discussion units
Trunk splitter
5 x 2 = 10 m
(32.8 ft.)
LBB 4114/00
Trunk splitter
LBB 4114/00
Trunk splitter
LBB 4114/00
Regenerative
‘Tap-offs’
Regenerative
‘Tap-offs’
100 m (328 ft.)
100 m (328 ft.)
240 m (787 ft.)
250 m (820 ft.) (max.)
Max. PCF = 17 at
240 m (787 ft.) acc.
to the graph. The
first two Trunk
splitters use 2 PCF,
therefore the PCF
value left at this point
is 15.
LBB 3500/xx
