page_title: Telegraph key
section_title: Alternative designs
hierarchical_section_title: Telegraph key / Types / Alternative designs
caption_attribution_description: Elektronische Morsetaste
context_page_description: A telegraph key is a specialized electrical switch used by a trained operator to transmit text messages in telegraph systems, usually in Morse code. Keys are used in all forms of electrical telegraph systems, such as landline or "wire" electrical telegraphy, and "wireless", or radio telegraphy. An operator taps on the switch, connecting and disconnecting the electrical circuit, creating electrical pulses of two different lengths called "dots" and "dashes", to spell out text messages in code.
context_section_description: In addition to the basic up-and-down telegraph key, telegraphers have been experimenting with alternate key designs from the beginning of telegraphy. Some are mede to move side-to-side instead of up-and-down. Some of the designs, such as sideswipers and semi-automatic keys operate mechanically. From the mid-20th century electronic devices called "keyers" have been developed, operated by special keys of various designs generally categorized as single-paddle keys and "iambic" or double-paddle keys.
  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 in both directions and the arm spring-loaded to return to center. A series of dits could be sent by rocking the arm back and forth. The alternating action produces a distinctive rhythm or swing which noticeably affects the operator's transmission style (known as his ‘fist’). Although the original sideswiper is now rarely seen or used, nearly all advanced keys use some form of side-to-side action.
  Semi-automatic key
  A popular side-to-side key is the semi-automatic key or bug, sometimes known as a Vibroplex key, after the company that first manufactured them. The original bugs were fully mechanical, based on a kind of simple clockwork mechanism, and required no electronic keyer. When the paddle is pressed to the left it makes a continuous contact suitable for sending dashes (or dahs, as most operators call them). When the paddle is pressed to the right, it kicks a horizontal pendulum which then rocks against the contact points, sending a series of short pulses (dits) at a speed which is controlled by the position of the pendulum’s weight. A skilled operator can achieve sending speeds in excess of 40 words per minute with a ‘bug’.
  Electronic keyers and paddle keys
  Like semi-automatic keys, the telegrapher operates an electronic keyer paddle by swinging the lever from side-to-side. When pressed to one side, the keyer electronics generate a series of "dahs"; when pressed to the other side, a series of "dits." Keyers work with two different types of keys: single paddle and double paddle keys. Like semi-automatic keys, pressing the paddle on one side produces a dit and the other a dah. Single paddle keys are also called single lever keys or sideswipers, the same name as the older side-to-side key design they greatly resemble. Double paddle keys are also called "iambic" keys or "squeeze" keys.
  Single paddle keys are essentially the same as sideswiper keys with separate contacts on the left and right. Double-paddle keys have two arms, one for each contact, both arms held away from the common center by a spring; pressing either of the paddles towards the center makes contact, the same as pressing a single-lever key to one side. For double-paddle keys, squeezing both paddles together makes a double-contact, which causes the keyer to send alternating dits and dahs.
  Most electronic keyers include dot and / or dash memory functions, so the operator do not need to use perfect spacing between dits and dahs or vice versa. With dit or dah memory, the operator's keying action can be about one dit ahead of the actual transmission. The electronic keyer  adjusts the timing so that the output of each letter is machine-perfect. Electronic keyers allow very high speed transmission of code.
  Using a keyer in what's called "iambic" mode requires a key with two paddles: One paddle produces dits and the other produces dahs. Pressing both at the same time produces an alternating dit-dah-dit-dah sequence, which starts with either a dit or dah depending on which side was pressed first.
  An additional advantage of electronic keyers over semiautomatic keys is that code speed is easily changed with electronic keyers, just by turning a knob. With a semiautomatic key, the location of the pendulum weight and the pendulum spring tension and contact must be re-balanced to change the dit speed.
caption: Electronic dual paddle keyer (homemade in 1972)
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