Bell System bellview - Page 52

Bell View Video System
Page 2 of 6
11 - 60 Way 2 Door Systems
Cable Requirement (Refer to diagrams 6a, 6b and 6c.)
Cable types (solid core)
0.5 mm Twisted pair, e.g. BT spec CW1308
1.0 mm 1.0 mm
2
‘Twin & Earth’
1.4 mm 1.5 mm
2
‘Twin & Earth’
Co-ax 75 Ohm, RG59 or equivalent
Video phones (each group of 10)
Total Cable Length Video Power (+,-) Other connections
(N = no. of video phones)
Video Signal
Basic Functions
25 m 9+N @ 0.5 mm [double +, -] 75 Ohm Co-ax
50 m 2 @ 1.0 mm 5+N @ 0.5 mm 75 Ohm Co-ax
100 m 2 @ 1.4 mm 7+N @ 0.5 mm [double V, O] 75 Ohm Co-ax
Basic Functions + Door Monitor Facility (L)
25 m 10+N @ 0.5 mm [double +, -] 75 Ohm Co-ax
50 m 2 @ 1.0 mm 6+N @ 0.5 mm 75 Ohm Co-ax
100 m 2 @ 1.4 mm 8+N @ 0.5 mm [double V, O] 75 Ohm Co-ax
Basic Functions + Camera Select Facility (CAM)
25 m 10+N @ 0.5 mm [double +, -] 75 Ohm Co-ax
50 m 2 @ 1.0 mm 7+N @ 0.5 mm 75 Ohm Co-ax
100 m 2 @ 1.4 mm 9+N @ 0.5 mm [double V, O] 75 Ohm Co-ax
Basic Functions + Door Monitor Facility (L) + Camera Select Facility (CAM)
25 m 11+N @ 0.5 mm [double +, -] 75 Ohm Co-ax
50 m 2 @ 1.0 mm 7+N @ 0.5 mm 75 Ohm Co-ax
100 m 2 @ 1.4 mm 9+N @ 0.5 mm [double V, O] 75 Ohm Co-ax
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, 5 common cables @ 0.5 mm and 10 individual call lines @ 0.5 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.