Many of our beta users have written to us asking why Teletype’s keyboard does not have a “1” key. This is not, as many of them have hurtfully assumed, the result of shoddy workmanship on our part. Instead, it is a deliberate design choice with some fascinating historical significance…

You see, our keyboard is modeled on typewriter keyboards from the 1930s, and it turns out they didn’t have a “1” key either. The incredible reason for this is—wait for it—the character “1” hadn’t been invented yet! In fact, the representation of “one” as “1” wasn’t proposed until 1948, and it didn’t achieve widespread use until the mid-1950s.

The modern digit “1” didn’t become widespread until the mid-1950s.

Before that time, the number one was represented by an uppercase letter “I” — a holdover from the Roman system of numerals. Because the two characters are so similar in appearance, modern viewers of historical texts seldom notice the difference.

Once you know what to look for, however, this amazing historical fact becomes obvious…

The Declaration of Independence. Note that the “I” in “IN CONGRESS” and the first character of “1776” are the same.

The pre-1950s representation of the number one in a car ad from 1914.

Which brings us back to typewriters. Since the number one and the capital letter “I” were still identical in the 1930s, there was simply no need for a special key for the number one—anyone wishing to type that number could simply type the letter “I” instead.

So if you’re writing out the date “APRIL 1” in a Teletype telegram, just remember to type “I” twice!