[7] Baudot's 5-bit code was adapted to be sent from a manual keyboard, and no teleprinter equipment was ever constructed that used it in its original form.

Once the keys had been pressed, they were locked down until mechanical contacts in a distributor unit passed over the sector connected to that particular keyboard, at which time the keyboard was unlocked ready for the next character to be entered, with an audible click (known as the "cadence signal") to warn the operator.

[9] The table "shows the allocation of the Baudot code which was employed in the British Post Office for continental and inland services.

In 1901, Baudot's code was modified by Donald Murray (1865–1945), prompted by his development of a typewriter-like keyboard.

An explicit SPC (space) character was introduced, in place of the BLANK/NULL, and a new BEL code rang a bell or otherwise produced an audible signal at the receiver.

code was introduced, which caused a receiving machine to send an identification stream back to the sender.

During long periods of idle time, the impulse rate was not synchronized between both devices (which could even be powered off or not permanently interconnected on commuted phone lines).

This sequence of pulses generated a series of Erasure/Delete characters while also initializing the state of the receiver to the Letters shift mode.

However, the first pulse could be lost, so this power on procedure could then be terminated by a single Null immediately followed by an Erasure/Delete character.

[clarification needed] Functionally, it can also play the same filler role as the Delete code in ASCII (or other 7-bit and 8-bit encodings, including EBCDIC for punched cards).

ITA2 is still used in telecommunications devices for the deaf (TDD), Telex, and some amateur radio applications, such as radioteletype ("RTTY").

ITA2 is also used in Enhanced Broadcast Solution, an early 21st-century financial protocol specified by Deutsche Börse, to reduce the character encoding footprint.

Unlike a typewriter or modern computer keyboard, the shift key isn't kept depressed whilst the corresponding characters are typed.

CR is carriage return, LF is line feed, BEL is the bell character which rang a small bell (often used to alert operators to an incoming message), SP is space, and NUL is the null character (blank tape).

Note: the binary conversions of the codepoints are often shown in reverse order, depending on (presumably) from which side one views the paper tape.

Thus FIGS (11011), LTRS (11111) and space (00100) are invariant, while CR (00010) and LF (01000), generally used as a pair, are treated the same regardless of order by page printers.

This tuning sequence is only useful when ITA2 is used with two-tone FSK modulation, such as is commonly seen in radioteletype (RTTY) usage.