Morse Code Keys and Devices

Straight key

The classic telegraph key: a bar with a knob on top and a contact underneath. Press it down and the circuit closes; let go and a spring opens it. You make every dot and dash yourself, so the timing is all in your hand. The first telegraph key was invented by Alfred Vail, who worked with Samuel Morse. Novices send around 5 words per minute on a straight key and skilled operators up to about 30.

American keys traditionally had short, flat knobs and European keys tall, ball-shaped ones. Railroad keys in North America also had a shorting bar, needed by the way those lines were wired.

Sideswiper

The first popular alternative moved side to side instead of up and down, with a contact on each side and a spring returning it to the middle. It was introduced partly for speed and partly to avoid “glass arm”, the repetitive strain injury that affected telegraphers pumping a straight key all day.

Semi-automatic key (bug)

A side-to-side key with a clockwork mechanism: press the paddle one way and a vibrating arm sends a string of evenly timed dots; press it the other way and you make a dash by hand. Skilled operators pass 40 words per minute on a bug.

Paddles and electronic keyers

Since the mid-20th century most operators use a paddle connected to an electronic keyer, a separate box or a circuit built into the radio. A single-paddle key sends dots one way and dashes the other. A double-paddle, or iambic, key has two levers: squeeze both and the keyer sends alternating dots and dashes, which makes letters like C (−·−·) very quick to send. The keyer times every element perfectly.

Try a key now

The translator has an on-screen key: open Tap, hold for a dash and tap briefly for a dot, or use the space bar on a computer. The tapping guide explains the rhythm.

Source

English Wikipedia, Telegraph key.