I have installed a few. It's legit.
Be forewarned, Toby has crammed a bunch of features into it. It will display the mode in use if you hook up two wires to a 9-pin socket on the rear to the radio's mode selector. Just one problem. You'll need to "invert" the usual "hot for that mode" voltages you can borrow from the radio's mode-selector switch.
In other words, you ground one wire to tell the thing you're on USB, ground a different wire for AM, and ground them both for FM. Leave both alone, and it defaults to LSB.
The radio won't have a circuit that provides those functions. We use a NPN transistor on each of the mode-select wires with the emitter grounded, a resistor from the base to the 'active' voltage for that mode, and the collector to the correct pin for that mode on the STB's accessory socket.
Kinda clumsy, but this also permits the STB to compensate for the change in the radio's 7.8 MHz carrier frequency when you change modes. The radio's original PLL had three trimmers for this. The STB has a number you set from a menu. But only if those two wires tell it what mode you've selected.
Hook it to the squelch circuit and it will scan for a channel that's occupied.
Unless you find a step-by-step with wire colors and pictures for your exact radio, the hookup requires some technical interpretation.
And once it's hooked up, it does exactly what it claims.
Every time so far, anyway.
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