Speed (wpm) vs Baud for TTY and Telex

This table shows the common baud rates and their corresponding data and stop bit durations. Telex speed is 50 Baud.

Baud Data (ms) Stop (ms) Stop Length (data bit periods) Speed (wpm)
45.5 22.0 22.0 1 65.00
22.0 31.0 1.41 61.33
22.0 33.0 1.5 60.61
50.00 20.0 30.0 1.5 66.67
59.92 17.57 25.0 1.42 76.68
17.57 26.36 1.5 75.89
74.2 13.47 19.18 1.42 100.00
13.47 20.21 1.5 98.98
100.0 10.0 15.0 1.5 133.33

The formulae are as follows:

Each character consists of a start bit, five data bits and a stop bit. The start bit and the data bits have identical durations while the stop bit may be the same or have 1.42 or 1.5 times the duartion of a data bit, hence:

Characters/second  =  1 / (6 x (data bit duration) + (stop bit duration)).

Characters/minute  =  60 / (6 x (data bit duration) + (stop bit duration)).

Words/minute (wpm)  =  (Characters/min) / 6  =  10 / (6 x (data bit duration) + (stop bit duration)).


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Last updated: 15 November 2001;    © Lawrence Mayes, 2001