Bell System bellview Installation & Operation Manual page 41

11 - 60 Way Single Door Systems
Cable Requirement
Cable types (solid core)
0.5 mm Twisted pair, e.g. BT spec CW1308
2
1.0 mm 1.0 mm 'Twin & Earth'
2
1.4 mm 1.5 mm 'Twin & Earth'
Co-ax 75 Ohm, RG59 or equivalent
Video phones (each group of 10)
Total Cable Length
Basic Functions
25 m
50 m
100 m
Basic Functions + Door Monitor Facility
25 m
50 m
100 m
e.g. 30 Video phones, with basic functions, and a maximum cable distance of 50 m required for each group of 10
phones;
2 common cables @ 1.0 mm,
Notes
A junction box MUST be placed within 2 metres of the power supply to split the common telephone wiring up into groups of 10
(video cables are already grouped by the VDC6 Video distributor) .
Assumes only 1 video phone is active at a time and the phones are distributed evenly along the cable run.
Loop the coaxial cable from phone to phone (daisy-chain wiring). Do not run a separate cable from each video phone back to
a common junction (star wiring). Where possible (for optimum speech clarity), a twisted-pair should be used for 'R' and 'O'
connections to the video phone.
Entrance
Connections
Camera + Speech unit
Push Buttons
Lock Release (up to 0.5 A)
Trades button (optional)
Exit button or Fire switch (optional)
Door monitor switch (optional)
No. of Phones
Bell View Video System
(Refer to diagrams 4a, 4b and 4c.)
Video Power (+,-)
9+N @ 0.5 mm [double +, -]
2 @ 1.0 mm
2 @ 1.4 mm
10+N @ 0.5 mm [double +, -]
2 @ 1.0 mm
2 @ 1.4 mm
5 common cables @ 0.5 mm
No. of Cores
6 + 75 Ohm Co-ax
1 per phone
2
1
2
20 2
60 2
Page 2 of 5
Other connections
(N = no. of video phones)
5+N @ 0.5 mm
7+N @ 0.5 mm [double V, O]
6+N @ 0.5 mm
8+N @ 0.5 mm [double V, O]
and 10 individual call lines @ 0.5 mm.
Max
Length
50 m
50 m
25 m
100 m
50 m
100 m
50
20
50
Video Signal
75 Ohm Co-ax
75 Ohm Co-ax
75 Ohm Co-ax
75 Ohm Co-ax
75 Ohm Co-ax
75 Ohm Co-ax
Solid Core
Diameter
0.5 mm
0.5 mm
0.5 mm
1.0 mm
0.5 mm
0.5 mm
0.5 mm
0.5 mm
1.0 mm