Bell System bellview - Page 46

Bell View Video System
Page 2 of 6
1 - 10 Way 2 Door Systems
Cable Requirement (Refer to diagrams 5a, 5b and 5c.)
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
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 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 + 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 6+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. 10 Video phones with basic functions over a 50 m length requires; 2 common conductors @
1.0 mm, 5 common conductors @ 0.5 mm and 10 individual call lines @ 0.5 mm.
Notes
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.