PARIS in Morse code

The player on this page times the word alone: 43 units, 2.58 seconds at 20 WPM. The speed standard counts one thing more, the seven-unit word gap after it, which brings PARIS to an even 50 units. At 20 WPM a unit lasts 60 milliseconds, so one PARIS with its gap takes exactly 3.00 seconds, and twenty of them fill the minute.

That gives the general rule: one unit, in milliseconds, is 1,200 divided by the speed in WPM. To check a keyer or a trainer, time a run of PARIS. At 20 WPM, ten of them should take 30 seconds.

PARIS stands in for ordinary language, with a word rate typical of plain text. The other standard word, CODEX, runs to 60 units and stands in for five-letter code groups, runs of random letters. At 20 WPM a unit is 60 ms by PARIS but 50 ms by CODEX, and speed records set under the two can differ by up to 20%.

American commercial licences used both. The FCC's words-per-minute tests sit close to PARIS and its code-groups-per-minute tests close to CODEX, and licences based on CODEX-standard code tests were still being issued in May 2013.

The city has a Morse claim of its own. On 17 May 1865 twenty countries signed the International Telegraph Convention in Paris, founding the International Telegraph Union, the forerunner of today's ITU. Its regulations required Morse code and its instruments, a rare case, the ITU notes, of the union naming particular equipment.