RADIUS
Product
Description
PDR221
iom_pdr221_04_r02.doc
Rev 02
Page 6 (60)
3 Introduction
Wireless communications remains the most cost effective solution for a significant amount of
modern applications. Advances in wireless technology allow data throughput and reliability to be
very high and, given the cost of direct cable, public networks or satellite infrastructure,
price/performance benefits remains far above other means of communication.
Modern wireless devices are much more than simple modems. They are sophisticated units,
designed to allow the user to create their own communication system with the minimum amount of
involvement.
The RADIUS PDR221, Packet Data Radio 221, transceiver provides wide range data telemetry for
control and monitoring systems using any communication protocol. The transceiver is designed for
point-to-multipoint operation environments including water, wastewater, electric utilities, distribution
automation, and gas field automation.
A PDR221 system consists of one master and up to 254 slave radio units. A PDR221 network can
contain one repeater. The repeater can operate stand-alone or with an RTU device connected. A
PDR221 network can, under normal circumstances, cover an area of at least 50 km from the
master.
The PDR221 is suitable for both polled and unsolicited systems. For unsolicited systems, there is
Collision Avoidance functionality built-in to the radio that virtually eliminates in-air collisions, vastly
speeding up the communication throughput. It is also possible to carry out Peer-To-Peer
communication.
The radio communication is completely packet switched, but the serial data is not buffered before
radio transmission, which increases the data throughput. The radio transfer data rate is selectable,
4800/9600 or 9600/19200 bps, depending on desired channel bandwidth, 12.5 or 25 kHz.
The radio modem uses a Forward Error Correction technique, which corrects a large proportion of
transmission errors in case of noise bursts. This feature significantly increases the radio sensitivity.
The PDR221 does not require any routing information, which makes the set-up and configuration
very easy. The configuration menus are accessed via a handheld terminal or a PC.
The control/monitoring device is connected to the PDR221 via a standard RS232 serial interface.
The serial interface speed is adjustable between 600 and 19200 bps, with or without parity. The
transceiver only needs a three wire connection, TxD, RxD and GND, but handshaking signals are
provided if required by the connected device.
The PDR221 provides diagnostic features, remotely changeable parameters, built in survey and
test functionalities. All easily accessed via a hand terminal or a PC.
