The DVMEGA GMSK board utilizes the CMX589 modem chip and is used as a shield for Arduino UNO, Arduino Mega 128 or Arduino Mega 2560. The Arduino controls the modem with the help of a freely available software. Received GMSK signals are decoded by the modem and are then transferred over the USB interface to an attached computer. Transmit-wise the digital data is sent from the computer to the Arduino and the modem, which then produces a GMSK signal used to modulate the attached radio. The connection to the radio is done over a standard 6pin MiniDIN Data connector.
A computer program is available for a Windows PC and for the raspberyr Pi. Using Yahoo groups, the author G4KLX offers various programs like ircDDBGateway and the PCrepeaterController. With these programs and above mentioned hardware a local hotspot for digital modulation can be built. The benefit is, that due to the use of a software programmable modem on the Arduino, the function can be adopted to future developments. For example it would be possible to extend the function of the modem not only to Icoms D-Star mode, but also to Yaesus ‘System Fusion’ C4FM modulation or other digital systems (e.g. DMR).
Please consider your local regulations concerning the construction and use of such radio systems. The combined products do not have a CE mark and should only be used by licensed radio amateurs.
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