BEEP
[/?]
[frequency [duration]] …
/?The BEEP command causes the PC speaker to emit a tone of the given frequency (given in Hertz) for the given duration (given in 1/18ths of a second).
More than one <requency,duration> pair may be supplied as arguments, in which case BEEP will emit each tone in turn. The final <frequency,duration> pair may optionally omit the duration, in which case the default duration is 1/9th of a second. If no arguments are supplied at all, the default is to beep at 440Hz for 1/9th of a second.