User guide
Doortello Business
Issue 1.00
Page 10
RS 485 serial interface (C/D)
External DC power supply (I/L)
Driver contact 1 and 2 (E/F; G/H)
Telephone line (A/B)
The unit must be connected to an analogue telephone line to work. The telephone
line can be a public line, an extension line or the input of a specific FXO adapter for
special networks like GSM, DECT or VoIP. Please take care that the open line voltage
should not be below 20 Vdc and it should be able to delivery a minimum of 18 mA
during the seizure. For the best speaker phone functionality select also the correct
line impedance (read also the chapter
Line impedance
).
Please note!
The Doortello Business door phone has a „fine“ over voltage protection. This is
useful only if more over voltage protection circuits are installed. If the unit is
installed outside a building we suggest the installation of a over voltage protector
with ground connection on the specific telephone line.
This interface is used for a communication with external devices, like the DB RU 1
unit. This unit has two more relays contacts which can be used instead of the
integrated ones to drive special applications (like TTL signals) or for the remote
control of the door opener if enhanced security is required. The RS 485 interface
can address up to 255 peripheral units.
The driver contacts can be used to open doors or other functions like the
activation of a video camera. As default the first driver contact is activated
pressing the DTMF digit „7“ during the conversation, and the second driver
contact with the digit „8“. Other ways to work are possible, like the automatic
activation with line seizure or after pressing a specific button. Also the activation
codes can be programmed, i.e. to make the door opening dependent from the
input of a code from the telephone. Read also the chapter
Programming
for more
information.
Please note!
The two driver contacts integrated in the Doortello Business door phone are
dry but not galvanic contacts as they are electronic circuits. That means that
diver voltage below 6 V may not work. In this case (i.e. TTL signals) you need
to use external relays, like the universal relay 1471 or DB RU 1 device (see also
Options
for more information).
The optional external power supply is used to power the door phone and to
activate some optional features. The external power supply is needed to activate
the following functions:
- Enhanced amplifier for noisy environments;
- Integrated heating element with temperature control;
- Illumination of the door station modules over the DB bus (max. 12 modules);
- Future enhanced features like speech announcements and display (not available
yet).
