3
30cm
165
cm
75º
165
cm
3. Selecting intercom sites and cabling
3.1 Intercom sites
The internal intercom should be located at a convenient position for all potential users
at the height indicated in fi g 3a and at a maximum distance of 70m from the external
intercom. If all the users are signifi cantly above or below average height then a different
mounting height may be considered appropriate.
The external intercom should be sited in an area away from driving rain
and surface water, out of direct sunlight as far as possible and protected by the
minimum of an open porch in a position readily accessible to potential entrants. It
should be mounted at the height indicated in fi g 3b.
Fig 3a
Internal intercom
mounting height
Fig 3b
External intercom mounting
height and coverage
3.2 Cabling
Connection between the internal and external intercoms is by 2 core cable and must not
be more than 70m long. Two core (13 x 0.2) bell fl ex is suitable.
A 15m length of 2 core cable is supplied with the kit terminated at one end with an RJ-
11 plug which connects to the RJ-45 socket on the internal intercom. Existing bell cable
runs can be made use of.
The cable run should be kept at least 100mm away from mains cables to avoid
interference.
A second relatively short 2 core cable will be required between the external intercom
and the door catch (if used).
A further 2 core cable will be required to extend (if necessary) the cable between the
external intercom and the second internal intercom for the DCEX4.
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