acoustic 'flag' for the RS232 interface

r. acoustic "flag" for the RS232 interface In the course of their work pro- grammers rarely use their sense of hearing. Why not use these inactive ears? Serial communication between a computer and its peripherals (no- tably the VDU) is in the form of pulse trains which make up the given transmissions. In the case of the Junior Computer and the elekterminal, for instance, the pulse width is determined by the trans- - 516 mission rate of 1200 baud; or 833 ps. which is of course within the audible frequence range! This fact gave rise to the idea of using these pulse trains as acoustic flags, thus allowing the programmer to concentrate on his screen, keyboard and especially his manuscripts, while entering data into memory. Similarly, while clearing the mem- ory (at the end of some particular type of research, for example) the user need no longer keep looking at the screen until the required out- put appears:. a string of $FF (or any other constant signal) gives an audible indication a...