Block Diagram - Bausch Datacom DinBox PSTN Reference Manual

2.

Block Diagram

The block diagram below details the location and interconnection of the different
functional units within the modem. The most important units are briefly described.
RS-232
RS-485
10 - 40 Vdc
Power Supply
The power supply (DC) must be connected to the DinBox PSTN(485) modem via a
terminal block with screw contacts. Make sure the voltage supplied to the modem is in
the range of the DinBox PSTN(485) input voltage (see specifications for details on
voltage range).
This input is protected against reversed polarity with a serial diode.
DTE Interface
The DinBox PSTN(485) modem has a RS-232 interface (RJ-45) witch can be
connected to a computer or similar device via included RJ-45/DB-9 serial cable.
The DinBox PSTN(485) has a buid-in 2-wire and 4-wire RS-485 interface.
PSTN Modem
The DinBox PSTN(485) modem has a Conexant modem chip. Connection with the
PSTN network is done via a standard RJ-11 connector.
Watchdog circuit
A long-term watchdog circuit is implemented. The power supply of the PSTN modem will
be disconnected for a few seconds after the selected reset period.
If a part of the DinBox PSTN(485) is 'locked' after e.g. an unexpected high ESD
discharge, surge pulse or an internal lock-up, this watchdog will always insure the
continuity of communication.
Bausch Datacom NV
DinBox PSTN Reference manual – V1.3
TxD RxD DCD
DTE
Interface
Power
Supply
Watch
DOG
7
PSTN
PSTN
Modem