Linux FRS Radio Control

Posted on Feb 5, 2014

This is a simple hardware computer interface and Linux program which can be used to control the most commonly used buttons on any consumer Family Radio Service (FRS) or General Mobile Radio Service (GMRS) radio. There are 22 available FRS/GMRS frequencies in the 462-467 MHz band. Each channel is also capable of 38 `private` subchannels. The subchann

Linux FRS Radio Control
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els are the result of using different Continuous Tone Coded Squelch System (CTCSS) tones, also referred to as "PL" tones, for each channel. By remotely controlling the Mode, Up Arrow, and Push-to-Talk (PTT) buttons, you can control just about any feature or function of the radio. This may be useful for anyone trying to build a store-and-forward "cellular" network using cheap FRS/GMRS radios (hint, hint). It`s possible to control other (or more) buttons with trivial hardware and software modifications. This particular example is built using a Cobra PR950DX FRS/GMRS radio (FCC ID: BBOPR950DXD) and a 74LS244 buffer/interface board. The radio`s buttons are active-low (ground to enable) logic, so the hardware interface is quite simple. The computer software was written to run under the Linux operating system. It`s not the best software in the world, but that`s because I`m stupid. I have no idea how to do this under Windows - or why you`d want to. The computer-to-radio interface hardware consists of parts (except the 74LS244) which are available at your local Radio Shack. The 74LS244 buffer IC is actually optional, as most computer parallel ports are limited to the amount of current they can source (output). This buffer will prevent any damage to your computer hardware should something short out, or if you need to control any additional hardware. The diagnostic LEDs are also optional, but are helpful to verify what the computer...

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