Digirig Mobile vs Signalink

I see the web searches for this topic so here is the summary:

  • CAT control - Digirig Mobile features a serial COM port which can be pre-configured to control most CAT capable transceivers. Signalink is not CAT capable.

  • PTT method - Signalink internally implements VOX (keys up radio when audio is detected), this method requires a delay adjustment (DLY knob) for each transceiver/mode/level. Digirig Mobile uses PTT control via CAT command or by RTS signal of the COM port, this ensures perfectly timed transceiver key up by the software. Every time, no adjustments are needed.

  • Interface - Signalink features multiple level knobs and status LEDs, Digirig Mobile has none. Yes, some operators like their shack looking like 70’s spaceship, but aesthetics aside there is no longer a practical need for that. Some settings have been automated (see PTT above), other settings (audio levels) are one-time set-and-forget and done in software. The benefits of minimalistic interface are especially evident with the rapid portable deployment.

  • Isolation - Signalink uses audio transformers and electromechanical PTT relay to implement ground isolation between the transceiver and computer. If desired, Digirig can be used with optional USB dongle to fully isolate computer from the radio including audio, PTT and CAT control. The majority of operators use Digirig without isolator and experience no adverse effects.

  • Bandwidth - Signalink’s audio transformers bottleneck its audio bandwidth. Although there were some improvements in later designs, the result still doesn’t come close to unconstrained 22KHz (44KHz sample rate) bandwidth of the Digirig covering any potential needs of ham radio.

  • Portability - In the blue corner at approximate size of the 9V battery and weighting a whooping 25 gram, the Digirig Mobile is less than 10% of Signalink size by volume and less than 15% by weight.

  • Cost - At the time of writing Signalink prices starts at around USD 140 including a generic cables kit. A comparable Digirig Mobile kit with better cables runs for under USD 80 or as low as $50 if you opt out for easy-to-build homebrew cables. Unlike with Signalink, you will not need to buy and swap jumper modules if you re-use the same interface with multiple transceivers cables.

One area where Digirig admittedly falls behind is the rubber feet department. There’s just no room for them unless they are comically small.

Use above categories as the template for comparisons with other interfaces. Here’s one by the makers of Signalink. The page from 1987 lacks Digirig entry but has BuxCom Rascal - whatever that may be…


I wonder if there is a comparison with ZLP Electronics DigiMaster MiniProSC
(Neil G4ZLP)

DigiMaster MiniProSC appears to be a Signalink clone that lost its knobs and using different codec IC, but equivalent in every other respect. Most of the above comparisons are applicable.


Urgh, I’d recommend rephrasing that. Maybe use “… to last a lifetime” instead. Otherwise it sounds like the interface is competing with the operator in longevity and might resort to murder.


Ultimately, none of these competitors are open source, and none release schematics which to me makes DigiRig the obvious choice.

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I have been reading about the configuration of the Digirig and it appears there has to be a selection of radio to get the configuration to suit your needs (solder jumpers). What happens if I want to use it amoung various radios that appear to need different configuration of solder jumpers? Do I need topurchase a second Digirig? Is this ONLY for CAT control on the selection of solder jumpers?

Yes, the jumper settings are for the serial CAT port configuration. You can share the same unit between multiple radios:

  • CAT capable radios that use the same CAT configuration
  • CAT capable radios that you use without (optional) CAT control
  • radios not capable of CAT control (HTs, most mobile radio)

I’m new to the digirig mobile but I know it’s an impressive piece of kit.

Rob K9OJ

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