Digirig Mobile (Digital-Mode Interface)
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| Frequency | n/a (digital-mode sound-card/CAT interface) |
| Power | A USB sound-card, CAT and PTT interface. No RF; it connects a PC to the rig for digital modes. |
| Modes | FT8/FT4, JS8Call, RTTY, SSTV, WinLink (VARA HF/FM), APRS/packet |
| usb | USB Type-C to the computer |
| audio ptt | 3.5 mm TRRS (TX audio, RX audio, RTS keying) |
| cat | 3.5 mm TRRS (RXD/TXD serial for CAT) |
| power req | USB bus-powered. |
All-in-one audio + CAT + PTT over one USB-C; tiny and rugged; wide OS and rig support; inexpensive.
Needs the correct rig-specific cable (sold separately); tiny jacks are fiddly; no galvanic isolation like some interfaces.
A pocket-sized, modern replacement for a bulky sound-card interface - one USB-C cable handles audio, CAT and PTT, which is why it's a POTA/SOTA favorite.
The Digirig Mobile is what the sound-card interface became once someone redesigned it from scratch for the FT8 era: a matchbox enclosing both halves of the digital-modes problem - a CM108-class audio codec and a CP2102 serial bridge - presented to the computer as one USB cable and to the radio as two 3.5-millimeter TRRS jacks. The audio jack carries receive, transmit, and HARDWARE PTT (ending the VOX-misfire era); the serial jack carries CAT control, with solder jumpers - set at order time via the shop dropdown, or re-soldered later - selecting logic-level, RS-232, CI-V, or TX-500 personalities so one board speaks every radio family's dialect. Per-rig cable kits do the pinout translation, which converts interface-building from a soldering project into a shopping decision.
The functional sweep is the modern stack entire: FT8 and FT4, JS8Call, Winlink over VARA, APRS through Soundmodem, the legacy modes besides - anything that wants audio in, audio out, and a push-to-talk line. The fifty-dollar price did the rest of the work: cheap enough to dedicate one to each radio, small enough to vanish into a go-kit, and complete enough that the previous default interface - bigger, costlier, VOX-keyed, and CAT-less - quietly became legacy gear the year the forums switched their reflexive answer to 'just get a Digirig.' (Its surviving niche is built-in transformer isolation; the Digirig's designer deleted the transformers deliberately, offering a $20 USB isolator dongle for installations that want galvanic separation.)
The honest notes are small: the jumper configuration rewards mild bench courage (preconfigured units exist for the rest), the TRRS world guarantees everyone one wrong-cable afternoon, and the clone worry runs ahead of the evidence so far - the maker's own forum investigated a 'suspect counterfeit' that proved to be a genuine older revision - though secondhand-marketplace buying still deserves the usual squint; the genuine article (Rev 1.11 as of this writing) ships from the maker's Colorado shop, the project of Denis Grisak. Its natural companions are whatever the shack runs digital on, from the pocket QRP class upward; its measure is that wiring any of them for FT8 now takes less time than the first CQ takes to decode.