It is possible to interrupt a program in progress, although it is not recommended, as it is important to complete the programs in their entirety. This is because these are not fixed frequencies, but each program contains hundreds of different frequencies. If it is still necessary to interrupt the program, the UP, DOWN and ENTER buttons must be pressed simultaneously. It should be noted that when you restart the device, it will not resume exactly at the point where it was interrupted. Each program has what are called subroutines. When turned on again, the program will resume at the beginning of the subroutine it was in, thus avoiding having to start the program from the beginning.