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MiriAD 2000 Modules |
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Radio Modems |
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Applications |
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450DR
Radio Modem
Download a detailed data sheet for this product 450DR datasheet
Miri offer a cost effective alternative to hard wired data transport.
Transmit your data over radio with a fully integrated 400-520MHz DATA RADIO MODEM designed for fixed point to point
and multi-point applications. The 450DR is a Half Duplex 400-520 MHz Radio including a fully integrated 9600 bps
Data Modem. The entire unit is housed in an attractive yet robust metal enclosure,
providing a compact and reliable data distribution product which is both cost effective and easy to install. This
complete package forms an attractively priced product for the transmission of data over Radio in fixed applications
thus providing a viable alternative to costly networks of buried media such as cable or fibre for data transmission. General
The modem includes a custom developed DSP for Byte oriented Packet Data
Communications over narrow band FM systems offering optimal data integrity and minimum occupied bandwidth. This
I.C. provides the interface between asynchronous RS232 host communication and the synchronous radio link layer.
It performs all data encoding, data shaping and filtering, clock recovery, NRZ/NRZI conversion, data randomising
and the HDLC coding, thus providing a complete, integrated serial data link front end with an absolute minimum
of external components. A unique fully integrated yet independent low speed Supervisory Data
Channel embeds a low speed data stream in the primary bit-stream transparent to the user of the primary channel.
This supervisory channel, which can be enabled or disabled under software control, may be used to pass low speed
data such end to end flow control, C/DSMA control schemes, etc. The use of this feature for collision avoidance
schemes makes this product eminently suited for reliable, error free data transmissions between stations in high
density point to multipoint networked data networks. Low occupied bandwidth and minimal sideband level are assured
with computer derived digital filtering, employing finite impulse response (FIR) techniques to minimise the recovered
signal integrity at the destination receiver. Diagnostics Transaction Processing -
Point of Sale Credit Terminals, Stock Control, Direct Order, Banks, Building Societies, Stock Brokers, Gambling
Organizations, etc, where Point of Sale, inventory, credit, or transaction data requires collection and distribution. Alarm Monitoring -
Fire, Power, Intrusion & Essential Services Alarm Reporting Common Carrier Data Services -
The high speed, low cost and spectrum efficiency of this device make it eminently suited to all forms of Common
carrier data networking.
The radio has been designed to meet world wide regulatory guidlines and has adjustable power output upto 5 Watts.
This fully synthesized radio is programmable in 6.25/7.5 kHz increments to accommodate various world wide channel
spacings. The receiver section has a wide tuning range with an excellent signal-to-noise ratio. A frequency stability
of ±1kHz is achieved by intelligent microprocessor controlled temperature compensation. An operating temperature
range of -10 to +600 C makes the unit ideal for commercial and industrial applications.
Data transmission uses HDLC protocol with CCITT CRC error detection. A fully configurable host interface provides
many connection protocols.
A large distributed network or even a simple point to point link requires comprehensive fault reporting and diagnostics
to ensure a high level of availability. The 450DR series of Data Radio Modem products offer sophisticated inbuilt
diagnostics. This capability allows the customer to remotely monitor and maintain their system, minimising the
likelihood of failures, by pointing out component degradation and decreasing the time to diagnose and repair. There
is no necessity to visit the master station or interfere with the host data integrity (diagnostics runs simultaneously
with the application), other than additional data transfer. The facilities offered include remote monitoring of;
transmit power, RSSI measurement, temperature, supply volts, transmit frequency offset and the ability to reprogram
parameters such as power output, data rates etc. within any remote unit in the diagnostics communications group.
In addition, the diagnostics data base allows the user to remotely perform a changeover of the duplicated base
station (if used) offering real time on screen telemetry indication.
Public Utility Telemetry Systems -
Gas, Water, Electricity Supply Authorities, Railways, County Councils etc, where network status, system control,
data collection and fault conditions are required to be known, and control or corrective action taken.