Connecting a USB Morse key or keyer to a Mac
A Morse key cannot plug straight into a Mac: a key is just a switch, and a Mac has no input made to read one. What works is a USB adapter, or a keyer, that shows up on the Mac as a keyboard and presses a key each time your contacts close. Plug it in, find out which key it types, and choose that key in the program you key with. Devices that show up as something other than a keyboard are a different matter, and this guide shows how to tell the two apart before you buy.
What is at the end of a key’s cable
A straight key is a switch with two contacts, closed for as long as you press, so it needs two wires. Paddles are two switches that share a common wire, so they need three: one for the dit side, one for the dah side and the shared one. The plug on the end varies from key to key.
None of that means anything to a Mac. Its USB ports expect a device that announces what it is, and its headphone jack is for sound. Push a key’s plug into the headphone jack and a keying program sees nothing. Something has to sit in between, watch the contacts, and tell the Mac in its own language that a key went down and came up.
Adapters and keyers that act as a keyboard
The simplest bridge is a USB interface that presents itself to the Mac as a keyboard. Each time your key closes, it reports a key press; when the key opens, it reports the release. macOS supports keyboards out of the box, so a device like this needs no driver, and any program that reads key presses can read it.
These come in three useful shapes, and until yours arrives, your Mac keyboard works as a Morse key:
| Device | What it sends | Set your program to |
|---|---|---|
| Straight key adapter | One key, held while the contacts are closed | Straight key |
| Paddle adapter | One key for the dit side, another for the dah side | Paddles, choosing both keys |
| Keyer with a keyboard output | One key, held for each dit and dah the keyer forms | Straight key |
The last row trips people up. A keyer that times the dits and dahs itself already does the paddle work, so what reaches the Mac is a perfectly timed single key. Set the program to paddles and it will look for two keys that never arrive. Set it to straight key and it simply reads the keyer’s timing. If instead your interface passes the two paddle contacts through as two separate keys, the program becomes the keyer, and it should be set to paddles.
Which key a device types depends on the device. Some type a letter or a symbol, some type a modifier such as Control, and some let you choose. The manual will say; look for words like “keyboard emulation” or “HID keyboard”.
Testing what your device types
Before you change any settings, find out what the Mac actually sees.
- Plug it in. Many recent Macs have only USB-C ports, so a USB-A plug needs a USB-C adapter.
- If macOS asks you to identify the keyboard, quit that window. The first time macOS meets a keyboard it cannot identify, it may ask you to press the keys beside the Shift keys, which a key adapter does not have. The next steps show whether the device works.
- Press the key in a text field. Open a notes app, click in an empty note and close the contacts once. If a letter or a symbol appears, the device is a keyboard that types that key.
- If nothing appears, it may be a modifier. Control, Option and Command type nothing on their own. A keying program that lets you choose a key by pressing it will show which one it is, which settles it.
- If nothing at all happens anywhere, check that the Mac sees the device: open System Settings, General, About, then System Report, and look under USB. If it is listed there but no keying program sees its presses, it is probably not acting as a keyboard.
A tip for adapters that type a letter: they are fine inside a keying program’s window, but keep them away from a document you care about, because every press in a text field is a letter.
Devices a keyboard-reading program cannot see
Some interfaces are made for radio software, not for typing, and the Mac sees them as something other than a keyboard, such as a serial port. Radio and logging programs read them in their own way. A program that reads Morse from key presses sees only keyboards, so to it these devices do not exist.
That is not a fault in either one; they are built for different jobs. If you already own one, check its manual for a keyboard mode. If you are buying, and the Mac is where you will practice, choose one that says it acts as a keyboard.
Two more things to know about a keyboard-type adapter. Acting as a keyboard, it talks to the Mac, not to a radio, and transmitting on amateur bands needs a license anyway. And the tone you hear usually comes from the program as a sidetone, not from the key, so set its pitch to taste; what pitch should Morse code be helps you pick one.
Using a USB key with Dot & Dash
In Dot & Dash, a USB Morse key or keyer that types a keyboard key works, as many do: in Settings, click the straight key (or the dit or the dah), then press your key; any key but Caps Lock can be chosen. Its Type Anywhere feature, which keys Morse into other apps, listens only for one of the six Option, Command and Control keys, so an adapter that types Space or a letter works in Dot & Dash’s own window but not there. How to type Morse code into any app on a Mac has the details.
Questions
Can I plug a Morse key into my Mac’s headphone jack?
No. The headphone jack is for sound, and a key is a switch. You need a USB interface that turns the switch into a key press the Mac understands.
Do USB Morse key adapters need a driver on a Mac?
One that acts as a USB keyboard does not, because macOS supports keyboards without extra software. A device that shows up as something else, such as a serial port, works only with software made to read it.
Why does my key work in the app’s window but not in other apps?
If it types Space or a letter, a program can only use it while its own window is in front, because in every other window that key types. Keying into other apps needs a key that types nothing by itself, such as Control, Option or Command.
Should the keyer time my paddles, or the Mac?
Either works. If the keyer forms the dits and dahs and sends one key, set your program to straight key. If the interface sends the two paddle contacts as two keys, set the program to paddles and let it do the timing.