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Assume a computer (Raspberry Pi, Mac, etc.) is used to connect to a radio (HF transceiver, etc.) via audio cable(s), USB port, or GPIO, etc.

What contemporary computer DSP/digital modes, of those popular and useful for low signal-to-noise ratio channels, can be used to communicate via just an ASCII text terminal for the computer? (e.g. no OpenGL GUI, Windows, VNC, RDP, CocoaTouch, no PPP/SLIP, etc., required)

For instance, there exists a utility for the Raspberry Pi that allows transmitting WSPR, controlled from either a serial port connection or an ssh terminal command-line. Any others? Any receivers? Any FT or JT or similar modes suitable for a full text-terminal-only QSO?

Added for completeness:

Do any of the recent modern software digital modes have existing specifications sufficient for implementation of the mode (e.g. writing DSP code rather than acquiring a "product"), and as part of the documentation, indicate how a QSO can be completely accomplished using just a terminal console (e.g. serial port connected dumb terminal)?

hotpaw2
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    No digital modes require a GUI, per se. What you are asking is what digital modes have software implementations that don't require a GUI, which sounds dangerously close to a product recommendation question to me. – Phil Frost - W8II Nov 15 '19 at 20:00
  • Do the operational requirements of the mode require implementation via a GUI or not? Can a blind person operate the mode via keyboard and braille output? – hotpaw2 Nov 15 '19 at 20:24
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    Prefer editing the question over commenting. Regardless, any digital mode I can think of could conceivably be operated by a blind person. Still, you're effectively asking for product recommendations. – Phil Frost - W8II Nov 15 '19 at 20:41
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    Question already specifies plain ASCII terminal. Blind users have used variations of such for many decades. I don't need a product. I need a mode suitably specified for a possible software implementation that can be operated without anything remotely close to a GUI. – hotpaw2 Nov 15 '19 at 20:50
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    Your question specifies in large, bold letters, "do not require a GUI". The answer provided certainly fits that specification. Don't get upset if people misunderstand if you refuse to be clear in your objective. – Phil Frost - W8II Nov 15 '19 at 23:42
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    Also I fail to see what it is about the specification of common digital modes (distinct from their software implementation) that precludes their use by a blind user. Perhaps if you were to elaborate in the question on what the specific difficulties were, you'd get more productive answers. – Phil Frost - W8II Nov 15 '19 at 23:45
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    "I don't need a product. I need a mode suitably specified for a possible software implementation" — I suggest that you put this into the text of your question. As it is, it's easy to understand your question as, as Phil Frost put it, "what digital modes have software …". – Kevin Reid AG6YO Nov 16 '19 at 18:38
  • "precludes their use"? I assume the opposite. Unusable unless documented by spec., or proven by existence: e.g. CW -> there exist many blind CW ops. – hotpaw2 Nov 16 '19 at 18:59
  • Are you asking "What contemporary digital modes [or available software for them] can be run *in a text-only display?*"? If so, you should edit your question to clarify that. – Mike Waters Nov 16 '19 at 20:01

2 Answers2

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You're confusing the transceiver implementation with mode as is.

Every single mode, as long as it's not used to transported to transport graphics, can be operated without a GUI.

Whether or not an implementation without a GUI exists is a different question, but honestly, coming from a world that's not Windows, this is basically the standard – be it FreeDV, WSPR, JT65... all these modes have libraries implementing them with which you can interact programmatically (typically: C bindings, although the original WSPR code is FORTRAN, IIRC), and thus especially with a shell.

Marcus Müller
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  • I have found libraries with narrow-band text IO bindings for WSPR, but no luck in finding any library APIs with a narrow-band text binding (e.g. suitable for keyboard input and with a readable single-channel text output) for JT or FT. Is such a library possible? For which modes? Any evidence? – hotpaw2 Nov 16 '19 at 02:27
  • as said, it's *possible* for all modes. – Marcus Müller Nov 16 '19 at 11:01
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    So, Thomas Habets wrote a [GNU Radio module for JT65](https://github.com/ThomasHabets/radiostuff/tree/master/jt65). As it's for GNU Radio 3.7, I haven't specifically looked at it, but from his [blog post](https://blog.habets.se/2018/11/JT65-with-SDR.html) it looks like you'd just remove all the graphical sinks in there, you'd end up with a plain flowgraph that just has the output message port which you can send basically anywhere – e.g. over network using ZeroMQ, or to a block written in python (about 10 lines of code) that interacts with a serial braille terminal. – Marcus Müller Nov 16 '19 at 11:10
  • That's really just to illustrate: If your mode is deterministic (and hopefully, it is – otherwise, it wouldn't be a mode but essentially noise ;) ), you can decode it with SDR. Having open specifications helps, but as the P.25 speech codec people, and many others, will tell you it's not strictly ... necessary, assuming someone has the time to reverse-engineer your mode. That's why I said "don't confuse the mode with the implementation": The mode really puts no restriction on how the interface to implementations look like. – Marcus Müller Nov 16 '19 at 11:15
  • Now, I'm naturally a bit worried when someone suddenly shows intense interest in Braille displays: @hotpaw2, are you doing alright? – Marcus Müller Nov 16 '19 at 11:16
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    Some of the iOS software I develop is designed for the vision impaired. More software should be. – hotpaw2 Nov 16 '19 at 14:20
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Here's one example:

NUE-PSK is a standalone, battery-operated digital modem using a Microchip dsPIC microcontroller. The project includes a character display for transmit and receive text data, and a graphic display showing band spectrum and tuning indicator. Using GPL open source software, the modem can be homebrewed for less than $60 parts cost. When coupled with an SSB-capable transceiver or with a popular PSK-xx transceiver board from Small Wonder Labs, you too can have an effective portable PSK31 station.

Note that the "graphic display" is another dot-matrix unit, like the multi-line text display.

enter image description here

Brian K1LI
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