User's Manual

INTRODUCTION

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234839, Revision 2.2

Introduction

RFI-9256 Data Strike 3 Spread Spectrum Radio Modem

RFI-9256 Data Strike Series3

Spread Spectrum Radio Modem Transceiver will open up new lines of

unparalleled high speed reliable data communications in hostile environments.

A Spread Spectrum Radio Modem has a wide band of frequencies allocated to it. The transceiver uses a

pseudo-random code to hop throughout this frequency band sending packets of data at different

frequencies. The receiver uses the same hopping code to synchronize and receive the data. This pseudo-

random code allows many radio devices to share frequencies and operate on independent networks on the

same frequency bands with negligible interference.

The RFI-9256 is essentially a full duplex radio modem capable of emulating a standard telephone

modem. The units can be configured for several types of standard link formats, including point to point

(Direct) where modems continually transmit to one another and point to multipoint dialup connections

where one unit can talk to many units by the use of a dialing mechanism to address the units. There is also a

protocol router mode, which can map protocol addresses to radios and forward the data to the correct unit.

The radio modems come from the factory configured as point to multipoint dialup.

The modem unit can be connected to a PC, laptop or any RS-232 device (e.g. terminals), to display the

inbuilt configuration menus or to directly control the operation of the modem via the inbuilt protocols.

One special feature of the modem is the two RS-232 ports provided (Main and Auxiliary). This allows the

user to monitor the operation of the radio whilst it is in communication with other units. Protocols on each

port are mostly independent of each other hence you can have two different protocols running

simultaneously.

Figure 1-1

shows a possible configuration for a pair of RFI-9256 units. The local modem is generally

configured as the Master and the remote/distant modem(s) as the Slave(s). It is the Master modems

responsibility to synchronise communication with other Slave modems, meaning a Master can initiate

communication with a Slave (and visa versa), but two Slaves or two Masters cannot communicate with each

other as communication will not be synchronised.

The RFI-9256 provides two methods of

configuration. There is a Menu System

and/or a set of Hayes

compatible AT

Commands available through either the

Auxiliary or the Main port. The menu

system provides a user-friendly interface with

prompts and the AT command set enables

the user to automate the operation of the

modem, by using scripts, and to dial remote

units.

Figure 1-1 Configuration Example for the RFI-9256