Editing Telegraph key (section)

===Alternative designs===
In addition to the basic up-and-down telegraph key, telegraphers have been experimenting with alternate key designs from the beginning of telegraphy. Many are made to move side-to-side instead of up-and-down. Some of the designs, such as ''sideswipers'' (or ''bushwhackers'') and ''semi-automatic'' keys operate mechanically.

Beginning in the mid-20th century electronic devices called ''[[keyer]]s'' have been developed, which are operated by special keys of various designs generally categorized as ''single-paddle'' keys (also called ''sideswipers''), and ''double-paddle'' keys (or "iambic"{{efn|name=iamb_trochee_note}} or "squeeze" keys). The keyer may be either an independent device that attaches to the transmitter in place of a telegraph key, or circuitry incorporated in modern amateurs' radios.

====Sideswipers====
The first widely accepted alternative key was the ''sideswiper'' or ''sidewinder'', sometimes called a ''cootie key'' or ''bushwhacker''. This key uses a side-to-side action with contacts on both the left and right and the arm spring-loaded to return to center; the operator may make a ''dit'' or ''dah'' by swinging the lever in either direction. A series of ''dits'' can be sent by rocking the arm back and forth.

This first new style of key was introduced in part to increase speed of sending, but more importantly to reduce the [[repetitive strain injury]] which telegraphers called "[[glass arm]]". The side-to-side motion reduces strain, and uses different muscles than the up-and-down motion (called "pounding brass"). Nearly all advanced keys use some form of side-to-side action.

The alternating action produces a distinctive rhythm or ''swing'' which noticeably affects the operator's transmission rhythm (known as ''fist''). Although the original sideswiper is now rarely seen or used, when the left and right contacts are electrically separated a sideswiper becomes a modern single-paddle key (see below); likewise, a modern single-lever key becomes an old-style sideswiper when its two contacts are wired together.

====Semi-automatic key====
[[Image:Bug telegraph key made by Weston Hadden, c. 1913 - Bennington Museum - Bennington, VT - DSC08642.JPG|thumb|Early "bug" telegraph key invented in 1913 by Weston Hadden]]
A popular side-to-side key is the semi-automatic key or "bug", sometimes known as a [[Vibroplex]] key after an early manufacturer of mechanical, semi-automatic keys. The original bugs were fully mechanical, based on a kind of simple clockwork mechanism, and required no electronic keyer. A skilled operator can achieve sending speeds in excess of 40&nbsp;words per minute with a bug.

The benefit of the clockwork mechanism is that it reduces the motion required from the telegrapher's hand, which provides greater speed of sending, and it produces uniformly timed ''dits'' (dots, or short pulses) and maintains constant rhythm; consistent timing and rhythm are crucial for decoding the signal on the other end of the telegraph line.

The single paddle is held between the knuckle and the thumb of the right hand. When the paddle is pressed to the right (with the thumb), it kicks a horizontal [[pendulum]] which then rocks against the contact point, sending a series of short pulses (''dits'' or dots) at a speed which is controlled by the pendulum’s length. When the paddle is pressed toward the left (with the knuckle) it makes a continuous contact suitable for sending ''dahs'' (dashes); the telegrapher remains responsible for timing the ''dahs'' to proportionally match the ''dits''. The clockwork pendulum needs the extra kick that the stronger thumb press provides, which established the standard left-right paddle directions for the ''dit''-''dah'' assignments that persists on the paddles on 21st&nbsp;century electronic keys. A few semi-automatic keys were made with mirror-image mechanisms for left-handed telegraphers.