Gira 1288 00 Operating Instructions Manual page 11

Door communication bus coupler
Video System
System
BUS
ET
The flush-mounted versions of the door and home stations are
connected to the 2-wire bus via door-communication bus
couplers.
Bus coupler jumpers
The accompanying wire jumpers must be attached between
BUS and ZV at the bus coupler in order for the colour camera/
TFT display to operate. Therefore the call button illumination
at the door stations can not be switched off.
The bus coupler has the following connections:
BUS
The devices are connected to the 2-wire bus via the BUS ter-
minals. Polarity need not be taken into account during con-
nection, as the polarity of the door communication bus is neu-
tral.
ZV
Floor-call button (ET)
With home stations, any push button (NO contact) can be
connected to the ET terminals as the floor-call button.
With the door stations, for example, a mechanical bell button
(NO contact) can be connected. This then acts like a call but-
ton from the Gira door communication system during start-up
and later operation.
The maximum cable length between the mechanical button
and the door-communication bus coupler is 20 m.
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