By using a BBC basic code program, a test equation for tones has been found online for a the picaxe sound command, audio tone results are listed here.
Below is the picaxe sound command as used for the 08m2 controller chip. The sound value of 121 produces a 1714Hz tone for a short period of time to measure the tone. A time unit is 10ms, so a 10 value would be 100ms.