Keyer
A device for hand signaling via switches, in telegraphy and computing.
A keyer is an electronic device used for hand-operated signaling through one or more switches. The term has two related but distinct meanings: one in radiotelegraphy, and another for computer-human interface devices.
In radiotelegraphy, a keyer specifically converts signals from an iambic or sideswiper telegraph key into Morse code, but does not include the key itself. For computer-human interfaces, "keyer" generally refers to both a single-hand multi-switch device and the electronics that interpret the user's key presses and send corresponding signals to the computer.
**Radiotelegraph Keyers**
In telegraphy, iambic keys evolved from earlier side-to-side, double-contact keys called "bushwhackers," and later from mechanical semi-automatic keys known as "bugs." Semi-automatic keys used a horizontal pendulum mechanism that automatically created a series of correctly timed "dits" when the lever was held to the right. The pendulum's timing was adjusted by sliding a weight toward the rear. The operator had to manually time "dahs" by pressing the lever left with the knuckle of the index finger, one press per "dah." Releasing the lever allowed springs to return it to center, breaking the contact and stopping the pendulum. Because only the "dits" were automatic, these were called "semi-automatic" keys. Modern electronic keyers automatically produce both "dits" and "dahs" as long as a switch is held, making them "fully-automatic."
Beyond convenience, these keys addressed a medical problem: telegraphers often developed a repetitive stress injury called "glass arm" or "telegraphers' paralysis," caused by forcefully pounding conventional up-and-down keys. Side-to-side motion avoided aggravating this injury and allowed disabled telegraphers to continue working.
With solid-state electronics, fully automatic keying became possible by simulating and extending mechanical keys. Special side-to-side keys, called iambic telegraph keys after the rhythm of telegraphy, were made to operate the electronics. In iambic telegraphy, the "dot" and "dash" are separate switches, activated by one lever or two. As long as the operator holds the lever left or right, the keyer sends a continuous stream of "dits" or "dahs." The operator sends codes by choosing the direction and duration of the lever hold. Even slightly erratic side-to-side motion still produces perfectly timed codes.
- Types
- Radiotelegraph keyer and computer interface keyer
- Keyer origin
- Fully automatic electronic keying became popular during the 1960s
- Key types
- Single paddle keys (bushwhackers, sideswipers) and double-lever iambic keys (squeeze keys)
- Switch count range
- Between four and fifty for computer interface keyers
- Medical condition
- Glass arm or telegraphers’ paralysis (repetitive stress injury)
Lore & Background
In telegraphy, iambic keys developed from earlier side-to-side double-contact keys called bushwhackers and mechanical semi-automatic keys called bugs. Semi-automatic keys used a pendulum mechanism to automatically create timed dits, while dahs were keyed manually. Modern electronic keyers automatically produce both dits and dahs as long as a switch is held, making them fully automatic. The side-to-side motion was also medically beneficial, as it avoided the repetitive stress injury known as glass arm or telegraphers’ paralysis, which was common with up-and-down straight keys.
With solid state electronics, iambic telegraph keys were made with separate switches for dots and dashes, activated by one or two levers. Single-lever keys are called single paddle keys, bushwhackers, or sideswipers; double-lever keys are called iambic keys, double-paddle keys, or squeeze keys. Squeeze keys allow both levers to be pressed simultaneously, producing alternating dit-dah or dah-dit sequences. Most modern transmitters have built-in keyer electronics, so an iambic key plugs directly into the telegraph jack.
In computer interfaces, keyers were inspired by iambic telegraphy. Inventor Steve Mann, mishearing iambic as biambic, generalized the concept to polyambic or multiambic keyers, such as pentambic (five keys) and septambic (seven keys) designs. These were used in early wearable computing and projects like BEHEMOTH by Steven K. Roberts. Computer keyers typically have 4 to 50 switches arranged in a hand-held cluster, differing from keyboards by lacking a traditional board.
Reader's Guide
The keyer holds significance as a bridge between manual telegraphy and automated electronic communication. In radiotelegraphy, it enabled fully automatic Morse code generation, replacing the semi-automatic mechanical bugs and reducing operator fatigue and injury. The iambic keyer allowed operators to send code with side-to-side motion, which avoided the repetitive stress injury known as glass arm. By the 1960s, fully automatic electronic keying became popular, and most modern transmitters now include built-in keyer electronics, making iambic keys directly compatible.
In the realm of computer-human interfaces, the keyer concept was adapted into compact, one-handed input devices for wearable computing. Steve Mann’s polyambic keyers, with multiple finger and thumb switches, were developed for early wearable systems and projects like BEHEMOTH. These keyers differ from keyboards by being hand-held and lacking a board, and they allow hands-free operation when combined with other functions such as holding a flashlight. The legacy of the keyer includes its role in reducing physical strain for telegraphers and its influence on modern chorded and wearable input devices.
Did You Know?
- The term 'keyer' has two distinct meanings: one for radiotelegraphy and one for computer-human interface devices.
- Semi-automatic keys called 'bugs' used a pendulum mechanism to automatically create dits, but dahs had to be keyed manually.
- Iambic keys are also called 'squeeze keys' because both levers can be pressed together to produce alternating dit-dah sequences.
- Inventor Steve Mann generalized the iambic concept into 'polyambic' keyers, such as pentambic (five keys) and septambic (seven keys).
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