Why Morse Code Gives Some Letters Less Work
A telegraph message traveled as a sequence of electrical pulses, sent when an operator pressed a key. Each pulse had to be made and heard—or read from a receiver—before the next one arrived. Shorter codes therefore meant less time spent transmitting a message, especially when a letter appeared again and again.
Morse code uses two basic signals: a dot and a dash. In standard timing, a dash lasts three times as long as a dot, and pauses separate parts of a letter from one another. A common letter such as E, represented by a single dot, can be sent quickly; a rarer letter gets a longer pattern. The system is “variable-length”: letters do not all occupy the same number of signals.
Turning Print Frequency Into Telegraph Speed
To decide which letters deserved the briefest patterns, the designers needed a practical estimate of how often each letter appeared. Counting the metal type blocks used by printers offered a rough measure: frequently used letters would have their type handled more often. That count translated a familiar feature of printing into a new engineering choice—how many key presses and pauses a telegraph operator would need.
The result was a code shaped around the labor of sending, not visual symmetry. Operators could move through ordinary text faster because its most common letters generally required the least signaling. A tiny decision about code length thus made a manual communications system more efficient every time a message was tapped out.
