EASIVOICE SYSTEM
ELECTRONIC INTERCOM SYSTEM
sec.2
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EASIVOICE
DOOR PHONE - VIDEO DOOR PHONE SYSTEMS: Installation Diagrams
Mod. 926
ELECTRONIC INTERCOM SYSTEM Mod. 926
INSTALLATION
WIRE SECTION
The section of the wires to be used depends on the distance between
the two intercoms furthest from the installation.
Note carefully the following table:
Should it be necessary to have larger installations, it would be possible
to resort to a solution in which more branches lead off from one point,
as illustrated in the fi gure below. In this case, the cross-talk effect
would remain unchanged within each individual branch ( the maximum
distance between any two intercoms must therefore be less than 200
meters). However, intercoms on different branches would not have any
effect on each other. This type of solution can also be used on normal
installations, i.e. for short distances, to further reduce the cross-talk
effect.
CONNECTION TO THE GENERAL CALL UNIT
A suitable amplifi er must be connected between the “A+” and the
“A-” terminals of the power supply in order to equip the installation
with a general call system. The amplifi er must have a 0,775 mV (or
dBm) input with an input impedance greater than 50 Ohm and with
its output power selected in function of the number and power of the
loudspeakers to be used.
It is recommended that the amplifi er be placed as close to the power
supply as possible and be connected to it with a shielded cable.
CONNECTION TO THE CALL STATION
Installation can be made with up to two Call Stations with automatic
switching (through a 788/1 relay box). Each Call Station must consists
of a Loudspeaking Unit and a certain number of call keys.
Power to the Call Station must be supplied separately by a dedicated
power supply (e.g. Ref. 786/1A). Connections to the loudspeaking unit
must be made through terminal 1A. The electric lock must be activated
through a Ref. 788/21 repeater relay. The door-opener is always a
“free door-opener”, i.e. the door can be opened at any time by pressing
the door opener-key.
INSTALLATIONS WITH ONE CALL KEY
A basic installation is one in which several intercoms (type 926/2) are
connected to a Call Station and can all answer a single call key. In
this case, when there is a call, all 926/2 intercoms will ring at the same
time. The fi rst intercom to answer will automatically exclude the other
intercom, thus ensuring conversation privacy. The maximum number
of 926/2 intercoms which can be connected in parallel depends, in
this case, on the total number of intercoms (926/1 + 926/2) in the
installation.
The following table summarizes the situation for standard installations
with just one power supply.
Number of 926/2
Total numbers
which can be connected
of intercoms
to a Call Station
(926/1 + 926/2)
on one call button
1
1
2
2
.
.
.
.
.
.
15
15
16
16
17
15
18
14
19
14
20
13
21
12
22
12
23
11
24
10
25
10
Note that when the total number of intercom door phones in the
installation is less than 16, they can all be type 926/2 and can be
connected to the Call Station on the one call key. As the total number
of intercoms in the installation is increased, the number of 926/2 which
can be connected to a Call Station decreases progressively to 10.
INSTALLATIONS WITH TWO OR MORE CALL KEYS
This type of installation is used in small buildings (2/4/8/ apartments)
where intercommunications and the “Follow-me” feature would be of
interest. In this case, the cable conduit would be 8 (or 9) + 4 + N wires,
which would limit possible applications to small user bases.
Type 926/2 intercoms must be used. They must be grouped in several
groups (usually 1, 2 or 3 units each), each of which is assigned to a call
key. When there is a call, all intercoms within the same group will ring
simultaneously. The fi rst intercom to answer will automatically exclude
the other intercom door phone in that group, thus ensuring secrecy of
conversation.
The table in the previous section remains valid, even though the
number of 926/2 intercoms that are connected to each call key is
generally 1 or at maximum, 2 or 3, in this type of installation.
Max distance (meters) 50
100
200
Section (mm
2
) 0,50
0,80
1
R (Ohm/Km)
35
21,8
17,5
EASIVOICE
