Home of the MultiDigi

Our current project is the MultiDigi, A dual QUAD radio capable audio and CAT control interface for Amateur Radio. The MultiDigi is continuously expanding, and for future expansion of your shack, I’ve made more improvements as I think of them.

The current feature set includes:

4 independent audio interfaces

4 port integrated USB hub for transceivers and other USB devices

4 independent serial / CI-V interfaces capable of 5V TTL and RS-232 voltage levels

Isolated USB uplink prevents ground loops and RF from harming your computer.

Wide input voltage range – 6 to 24 volts and can share the power source from your radio.

September 10, 2017 – Update September already? wow, where has the time gone?Testing on second revision has yielded great results. The performance has been rock solid with no failures whatsoever of the design. Audio subsections continue to be well behaved and no issues with all data modes. Serial communications likewise continue proper operations. Morse code via the RTS/DTR lines is a great bit of fun. SSTV on VHF is flawless. It’s working far better than I ever imagined.

In the works – Finalizing the next revision prototype, including two additional audio sections, revamp of the integrated USB hub to provide 4 downstream outputs, implementation of RJ45 jacks for serial and switching interconnections. Also, thinking of a NIMH battery unit in a matching enclosure for emergency or field operations. Currently, the multidigi will operate about 2 days on a 9v battery, but a weeks worth of power wouldn’t be a bad thing.

February 1, 2017 – Update Testing continues on second revision, Did locate an interesting item for the Kenwood TS-480 serial connector today, which I had forgotten and isn’t anywhere on the web (what gives guys) anyway before you spend 5 hours tracking this issue down yourself I’ll share it here.

January 10, 2017 – Update  The project is back on track, I am in process of finishing out the board set for fabrication. I should be able to get them sent out within the next few weeks for the third prototype run. Once I am certain that they are 100% functional without error, I plan to begin a Kickstarter campaign for orders.

November 15, 2016 – Update The project is on temporary hiatus due to life, we are selling our home and things are quite in a state of disarray. I have mostly completed the Revision 3 boards so far as design goes, but have yet to get them complete then need to get them fabbed and tested before launch. Have been off air for over 45 days now, I am having HF withdrawl!

June 18, 2016- Well, after playing with several ideas for the front panel, I have decided on the following design as it fulfills all the requirements of the unit, and is very clean and user-friendly IMO!

MultiDigi Face 1d Final

May, 29, 2016 – Playing with ideas for the front panel layout. The characters in BOLD (ON, RTS, DTR, and PTT) are translucent on the first two panels, and designed to be backlit with LED only showing up when they are active. Right click and open in new tab to see image better.

Multidigi Front Panel Opt 1

Multidigi Front Panel Opt 1

Multidigi Front Panel Opt 2

Multidigi Front Panel Opt 2

Following layouts will be a through hole led:

MultiDigi Front Panel 3

MultiDigi front panel option 3 with through leds

May 15, 2016 – The Rev3 MultiiDigi main circuit board design is now completed. In work are the front panel circuit board, level shift boards and front and back end panels. Those are not nearly as complicated, so should not take a huge amount of time if I can get into my designing zone. -Shawn


Updated 4-30-2016 – Evolution continues!

MultiDigi Rev2

MultiDigi REV 2

The Rev 3 Release candidate continues to evolve with feedback from our beta tests and live experimentation on the Frankenstein Rev 2 Test unit. New implementations of EMI/RFI filters has reduced RFI on the incoming data signal lines from 1.5v p-p to roughly 30mv p-p ensuring solid data communications and vastly reducing false data issues.

The Silicon Labs CP2108 UART chip is doing great, and thanks to Silicon Labs PID program, we have our own Product Identifier in the USB chain.

MultiDigi Devices

As you can see, the Silicon Labs UART is customizable and includes the MultiDigi named devices vs the FTDI generic listings in yellow. This was done for the sake of making it easier to locate and assign com ports for software and interconnection with your radio and communications gear.

The back panel connectors have all been changed to RJ-45 modular jacks, While our pin configuration is not a standard, it is easy to replicate and create your own interconnections to your equipment. The Audio connections now incorporate a selectable RTS/DTR pair for PTT keying via the audio patch cable, the data connections are now all capable of serial communications as well as RTS/DTR switching duties.

The RTS/DTR pairs are also now fully isolated via optocouplers and rated to 80v 50ma switching duty.

Also implemented in this revision is a pluggable card method to select TTL or RS-232 voltage levels depending on your needs. This was a requirement based on the fact that not all communications gear is created equally. Icom CI-V interfaces, for example, are 5v TTL logic, while a Kenwood DB-9 serial interface is at +/- 15v RS-232 signal levels. To ensure compatibility with your equipment, and make an easily configurable device, the plug-in card method allows you to set the logic level needed, without hassles of a multitude of jumpers to misconfigure.

Currently at revision 2, it has proven to be a successful design. As of this writing, I have over 1000 contacts logged using a MultiDigi, as with any new designs, there are a few bugs which are being addressed in the upcoming Rev 3 version.  There is also an opportunity for beta testers, if interested please drop me a note at kd6oji@gmail.com.

MultiDigi documentation can be found here: Multdigi Operating Manual