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The Autodialer permits a remote DNP3 intelligent electronic device (IED) to
transmit "Unsolicited Messages" or report-by-exception over a dial-up line.
This capability is often a requirement for electric utilities using DNP3 and
dial-up for Poletop RTUs and Independent Power Producers (IPPs).
Where dial-up access to a communication channel is required, there are
currently two choices: A modem designed for DNP communications, able to intercept data and initiate
a dial-out procedure; or a conventional modem in conjunction with the Autodialer module. In the latter
case, any modem can be used to initiate communications, and the end result is a more cost-effective and
modular system.
In a typical DNP system, when data must be reported through a communication channel,
it is simply transmitted. The Autodialer sits between the DNP system and the modem, monitoring the
system for communication activity. If activity is sensed, the Autodialer will sieze the channel, and
establish a dial-up connection via the modem. Once this is established, control will be returned to the
DNP system, and data may be transmitted. As this is a non-handshaked mechanism, the DNP system must be
configured to transmit relevant data at least three times in order to give the system a chance to establish
communication.
The unit has the following feature set:
- Default communication speed of 9,600 bps.
- DIN rail mountable enclosure.
- Built-in self-test mechanism.
- Reset Switch.
- Up to 28V DC unregulated power input.
- Field programmable using standard RS-232 cable.
- No special software required, can be programmed using any terminal emulator.
- 94V0 Rated PCB.
For further details, viewable with Acrobat Reader, see the following documents:
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Developed in response to customer need, this product performs the simple
task of making a CDPD modem available to a standard serial port on a PC or other piece of industrial
equipment. The CPDP modem in question, a Sierra Wireless SB300, provides only an FFC ribbon cable
connection with 5V signalling. The carrier board not only breaks out the difficult-to-work-with FFC cable
but performs the task of level shifting all signals so that any data terminal equipment may be used
for communication.