Ingress: cocoaModem, the classic W7AY Mac digital-mode application, has been brought forward for current macOS as a universal Apple Silicon and Intel build. The 2.1rc5 release keeps the multi-mode personality intact, adds practical RTTY and integration updates, and makes Wideband/Dual RTTY especially interesting for DXers working split pileups with main and sub decode.
From preservation project to usable modern Mac app
cocoaModem has always been one of those applications that feels purpose-built by an operator who understands radio, not by someone chasing a software trend. The challenge with bringing it forward was that the original codebase came from a very different macOS era. The work was not a redesign and not a rewrite. The goal was more respectful than that: preserve the original structure and operating model created by Kok Chen, W7AY, then do the compatibility work needed to make it build, launch, and behave on current macOS.
That journey touched the parts you would expect in a mature Mac application: modern Xcode project settings, current macOS runtime behavior, Intel launch compatibility, application identity and versioning, native appearance, transmit text handling, automation permissions, and the audio and hardware integration edges that matter in a real station. The result is a familiar cocoaModem, but one that has been pulled back onto modern Apple Silicon and Intel Macs.
What is included
The release keeps cocoaModem broad. It is still a multi-mode macOS modem application, with Wideband RTTY, Dual RTTY, PSK and PSK31-oriented operation, CW, MFSK and DominoEX, Hellschreiber, ASCII, SITOR-B, HF-FAX, and synchronous AM in the application tree. It also keeps the operating tools that made cocoaModem useful beyond casual receive: audio device selection, waterfall and spectrum displays, aural monitoring, QSO and contest workflow, AppleScript support, PTT and keyer interfaces, and macro-driven transmit operation.
For contest and DX work, the bundled resources include familiar exchange and RTTY contest setups such as RTTY Roundup, CQ WPX RTTY, BARTG, EA RTTY, SP RTTY, XE RTTY, TARA, generic exchanges, RST exchange, and serial-number style resources. That matters because the app is not only a decoder. It is built around operating.
Why RTTY still matters
RTTY has not disappeared from serious DX work. It is still heard in contests, still appears in DXpedition mode plans, and still has a loyal group of DXers who appreciate a mode that is narrow, direct, and well understood. When a rare one runs RTTY, the pileup can be just as tactical as on CW or SSB. You need to decode the DX station, watch where they are listening, and understand the caller stream well enough to choose a smart transmit frequency.
This is where cocoaModem becomes especially attractive. Wideband RTTY and Dual RTTY instantiate both a Main Receiver and a Sub Receiver. In practical pileup terms, that means one receive path can stay on the DX signal while the other follows the split area or a second slice of the caller activity. It is a simple operating advantage: less guessing, more listening, and a better chance of understanding the rhythm before you transmit.
FSK, AFSK, macros, and logger integration
RTTY operators care about keying. The current modernization includes external FSK keying support for RTTY operation, while the traditional AFSK path remains part of the application. That gives station builders more flexibility, especially where hardware, serial interfaces, or keyers expect true FSK control.
Macros are equally important. In RTTY, the difference between a smooth QSO and a clumsy one is often the quality of the CQ, call, exchange, TU, QRZ, RX, and TX handoff messages. cocoaModem retains macro sheets and contest macro workflows, and the RC5 work also cleaned up unsupported transmit punctuation paths so macro and transmit text handling is better behaved on modern macOS.
There is also a modern contest integration angle: cocoaModem 2.1rc5 exposes fldigi-compatible XML-RPC methods for RumLogNG-style workflows. That allows logger-side transmit and receive coordination without giving up the cocoaModem operating surface.
Download
At the time of writing, checked on 7 June 2026, the current public GitHub release is cocoaModem 2.1rc5, published on 16 May 2026. The release asset is named cocoaModem-2.1rc5-macos-universal.zip.
The package is a universal macOS application for both Apple Silicon arm64 and Intel x86_64. Download the ZIP from the GitHub release page, unzip it, and launch the app on the Mac you use for radio. As with any serious radio application on modern macOS, allow the permissions your station setup requires, such as microphone or audio input access, automation access, and serial or keyer access where relevant.
A classic worth keeping alive
The best part of this update is that cocoaModem still feels like cocoaModem. The modernization does not bury the original idea under a new skin. It keeps the application useful for the operators who value its wide mode coverage, its RTTY tools, its macro-driven rhythm, and its Mac-native feel. For DXers who still chase RTTY, especially when a DXpedition lights up the pileup, the Main and Sub receiver capability alone makes this release worth a fresh look.