Here’s an example of the audio received from a SM1000:

SM1000 FreeDV Adaptor

The SM1000 allows you to run FreeDV without a PC. Connect the SM1000 to your SSB radio, and you now have Digital Voice (DV). You don’t have to buy a new radio to run Digital Voice! It’s based on a STM32F4 micro-controller, has a built in microphone, speaker amplifier, speaker, and transformer isolated interfaces to your radio. It’s just 80 x 100mm, and can be held in you hand and used like a regular PTT microphone. Or it can sit on your bench and work with your favourite headset.

The SM1000 was developed by David Rowe VK5DGR and Rick Barnich KA8BMA. It is being manufactured, tested and shipped by our good friend Edwin at Dragino in Shenzhen, China.

The SM1000 is completely open – hardware and software – including the Codec 2 vocoder. The licenses encouraged you to modify the software and hardware, under the condition that you share your modifications.

The rig audio and PTT connections are 3.5mm sockets in parallel with a RJ45. A small patch panel can be used to configure the RJ45 pin out for your radio. You need to supply suitable audio cables, e.g. 3.5mm or RJ45 to your radio. The SM1000 operates from 8-16V (12V nominal) and uses approximately 200mW. Perfect for mobile or SOTA work! It also has a USB port for firmware updates from a Windows or Linux PC.

The SM1000 supports “analog pass through”, FreeDV 1600, 700D and 700E modes. The SM1000 firmware can be upgraded via USB.

The “analog pass through” mode can be used to make SSB contacts without having to swap microphones. Press the SELECT button and it’s 1600, another press 700D, the next 700E, then one more press and you’re back to analog pass through for SSB. A LED indicates microphone level clipping on transmit and errors on receive. Levels (to and from your radio and mic gain) are set using trimpots.

World Wide Orders

Please order from our Tindie store for shipping direct from China via EMS courier or e-packet. Please note prices are exclusive of local taxes and import duties.

Australian Orders

September 2023 – New stock is expected in the Australian store soon.

If you live in Australia just click the buttons below to order your SM1000 via PayPal. If you don’t have a PayPal account you can use a credit card at the end of the check out process.

The price below includes shipping via Express Post.

Adelaide customers: I will refund your shipping ($19.95) if you pick up. Please add a note to your PayPal order that you would like to pickup, otherwise I will Express Post to you. The store forces shipping for legacy reasons.

Item Price
SM1000 (Australian Customers Only) including shipping AUD$195.00 + shipping

Important If you live outside of Australia please order from Tindie store. International orders using the Australian option will be immediately refunded and directed to the Tindie store.

What you get

The SM1000 is supplied with a sturdy metal enclosure, a USB programming cable, and jumper wires for the RJ45 patch panel. Their is no documentation supplied with the SM1000. Instead, there is an on line Manual.

What you have to supply

You need to supply a 2.1mm plug centre positive 12VDC (nominal) power source, patch cables to connect the SM1000 to your radio, and the wiring diagram for your radio’s microphone connector.

You will need a few hours of your time to assemble cables to connect the SM1000 to your radio.

This is the hardest part of SM1000 set up. Please make sure you are comfortable with schematics, soldering, designing and making cables, and putting the time into understanding your rigs microphone, speaker, and PTT connections.

Sorry, we do not have specific instructions for your radio.

SM1000 Support

Read the SM1000 Manual.

For SM1000 support or just to tell us about your SM1000 experience please post to the Digital Voice Google Group.


Parameter Value
Modes Analog, FreeDV 1600, 700D, 700E
DC Power Input CN3 8-15VDC, 200mW max
Rig Mic Output CN7 0.5 to 50mVpp
Ext Mic Input CN5 1000 (Jumper J3 in place) or 2000 (Jumper J3 removed) ohms AC impedance
Rig PTT Output CN9 Floating, less than 100 ohms on resistance
Ext Speaker Output 4 ohms min, 700mW max power into 8 ohms with 12V power input voltage


Read the SM1000 Manual
SM1000 Support Digital Voice Google Group