RiTTO TWINBUS, System Manual

Page: 11 / 197

General Information
11
General Information
1.4 The video system
Installation requirements for video cameras
A camera can only view a certain area. In order for the visitor who has just rung to be monitored, for example, the
camera must be appropriately installed.
The surveillance area varies according to the angle the camera module is set.
The installation height is approx. 1.5 to 1.6 m.
„
The area surveilled must be well illuminated, also at night. If necessary, appropriate lighting must also be installed.
„
We recommend positioning an external light about 1 m above the camera. It should be an incandescent bulb of
at least 40 W.
„
The camera must not be pointed towards the source of light (sun, lighting, reflection, etc.).
Terminal resistor
Circuit diagram: terminal resistor for mixed systems.
A indoor video station as the last device in the line
* Terminal resistor: ON
B indoor video station as the last device in the line
** Terminal resistor: OFF
Note:
You must switch on the terminal resistor if the indoor video station 1 7857 or 1 7855 or handsfree
video intercom unit 1 7835 or 1 7845 you want to install is the last device in the video bus line.
If the last device installed in the video bus line is an indoor video station 1 7815 or 1 7825, manually
use a 100
Ω
resistor 1 7832.
Caution!
Reduced image quality
Incorrectly set terminal resistors will lead to reduced image quality.
1 7857
1 7857
Va Vb Va Vb Va Vb
))
*
Va Vb Va Vb Va Vb
1 7815/25
1 7815/25
S0121-0