Beep

   10 REM Beep port routine
   11 REM 
   20 REM Lower RAMTOP
   21 REM 
   30 RESTORE : LET x=(PEEK 23730+256*PEEK 23731)-43: CLEAR x
   40 REM 
   41 REM POKE Machine code
   42 REM into memory
   43 REM 
   50 LET x=(PEEK 23730+256*PEEK 23731)+1
   60 FOR y=x TO x+42: READ z: POKE y,z: NEXT y
   70 REM 
   71 REM Print USR Address
   72 REM 
   80 PRINT AT 1,2;"The routine is called by the";TAB 7;"function USR ";x
   90 REM 
   91 REM Example
   92 REM 
  100 PRINT AT 12,10;"Press any key"
  110 IF INKEY$="" THEN GO TO 110
  120 LET a=USR x
  130 GO TO 110
  200 REM 
  201 REM Machine code data
  202 REM 
  210 DATA 58,72,92,31,31,31,230,7,14,255
  220 DATA 38,0,68,203,231,211,254,16,254,68
  230 DATA 203,167,211,254,16,254,203,231,211,254
  240 DATA 16,254,203,167,211,254,16,254,36,13
  250 DATA 32,226,201