This is our achievement after many hours of past and continuing work, the MultiDigi.

The MultiDigi was born out of curiosity, challenge, and stubbornness.

I was curious about a full featured computer – radio interface that would unload the burden of sound and digital control from my rather limited supply of USB and sound ports on my laptop. I enjoy listening to podcasts while operating soundcard modes on the radio. My radio is capable of being controlled by software to change frequencies and settings.

I had found a few commercially available products that would almost fit my criteria, however, being on a school budget didn’t allow the purchase of an expensive unit, much less two of them.

The challenge came from my muddling around with many of the DIY projects available, but none of which, while they did work, were not a very elegant solution. What if I could design my own?

My criteria were identified as so:

Run from a single USB port.

Provide audio and serial data output to the radio.

Provide for auxillary switching for things such as computer CW, PTT, etc.

And in an act of mutually assured destruction, run two transceivers at a time without having to swap cables.

Well, I was successful. The first revision was quite buggy, and many errors were accomplished. Who needs bypass capacitors anyway? Power input to chips? naw, those don’t need poower, they run on magic! After several days of debugging and adding parts that were omitted as uneeded, I soon learned the datasheets and demonstration schematics know their devices much better than I. I added many bypass capacitors, and even figured out how to hand solder bodge wires to 0.4mm SMD IC’s to feed them power. Not a very fun endeavour, but hey, it was a prototype.

In the second revision of the prototype, I’ve resolved many of the errors from the first version, but still have a few things that need remedied, as well as implementing other features for other ideas that have been asked about or thought of.

I have really enjoyed the challenge, and have learend a lot about high speed USB signaling. and radio interfacing in general.

Revision 3 will build upon this success and include both RS-232 and TTL level data outputs to further compatability, as well as improved EMI filtering on all sound and data lines.

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MultiDigi REV 2 prototype