This page is no longer updated, use AS-IS for reference only!!!


SUCCIv1 is not rich in features but this is actually the idea behind - simple and (I believe) cheap device that you could throw wherever you want. A list of the features follows:

  • USB interface towards PC/laptop with mini USB type B connector
  • Optoisolated CW and PTT open collector outputs connected to respectively the DTR and RTS lines
  • FootSwitch (FS) input with RF blocking circuit activating the DSR line
  • CAT terminal for radios with TTL-level based control interface that utilizes RF blocking circuit.
  • Jumper selectable single-wire (Icom CI-V) or double-wire (Yaesu style) CAT terminal output.
  • LED-based indicators for CW and PTT signal status.

Supported radios

CW and PTT functions are supported on virtually all radios that switch less than +70VDC and 30mA on their CW&PTT inputs, but no more than 100mW per input. You radio should be supported in case it was produced during the last 25 years.

Computer control (a.k.a. CAT) is supported on the following radios:

  • all Icom transceivers with CI-V interface
  • the following Yaesu models: FT-100, FT-817, FT-840, FT-857, FT-890, FT-897, FT-900, FT-990, FT-1000(D)

Other radios that utilize TTL voltage levels for computer control might be supported as well but were never tested.

Theory of operation

The heart of SUCCIv1 is USB to UART module, based on Silicon Labs' CP2102 chip. There are several reasons for using this specific module:

  • easy to solder, since all of its terminal are spreaded on a 2.54mm grid.
  • relatively low cost
  • stable drivers

The TTL-based serial terminals of the chip are then connected to the respective outputs with very few supporting elements - current-limiting resistors for the CAT, LC-based RFI filters for both CAT and FootSwitch terminals, optocouplers for CW and PTT isolation (in case you are going to use it on a radio with high voltage levels on these inputs). In addition to that, LEDs for CW and PTT status monitoring are placed so you always know whether these signals are going out of the USB to UART module or not, thus helping you to troubleshoot PC or optocoupler issues. Eventually, all the terminals are available on standard and easy to use RCA cinch and 3.5mm stereo jack plugs.

Connecting SUCCI

Connection to your PC is established through the board's USB mini-B connector. In case your computer fails to automatically install the respective drivers, these can be obtained from the following link.

Your radio's CW key input should be connected to the red RCA jack. My personal choice goes for standard stereo jack to red & white cinch cable, the tip of the red cinch on the cable is (usually) terminated on the jack's tip and the white cinch is either isolated or removed.

If your radio has cinch as PTT input, standard cinch-cinch audio cable can be used for this connection as well. If not - you'll have to do some soldering. White-coloured cinch connectors are recommended in order to keep the color scheme.

Footswitch input (the yellow one) is active when shortened, so normally it is expected that your footswitch has N.O. contact and a (yellow) cinch connector.

Radio control (a.k.a. CAT) is terminated on a 3.5mm stereo jack. It makes all Icom owners' life easier because (again) standard 3.5mm jack to 3.5mm jack audio cable fits perfect. Non-Icom owners should exercise their soldering skills. Selection for Icom/Non-Icom radio is done by JP2 on the board with positions 1-2 for Icom and 2-3 for non-Icom.

User Guide & Schematic

Both User Guide and Schematic documents are available at the files section on the bottom of the page.

Obtaining SUCCIv1

SUCCIv1 is no longer produced.

Please check the SUCCI project page for most recent developments. This page and the respective documents will stay as reference as long as the site is alive.

SUCCI v1.1