5000 REM THIS PATCH TO THE COMM SOFTWARE THAT COMES ON THE DOS DISK USES
5010 REM A RESIDENT ROUTINE TO PERFORM A PROGRAMMED BACKSPACE
5020 REM (SUB 2720). IT CHECKS EACH CHARACTER AND EXECUTES BACKSPACE
5030 REM AS REQUIRED. LINE 5115 IS OPTIONAL AND PROVIDES FOR PRINTING
5040 REM OF THE KEYBOARD AND OTHER INPUT DATA UTILIZING THE PARALLEL
5050 REM PRINTER PORT. THIS CAPABILITY IS ACTIVATED BY ENTERING VALUE
5060 REM IPRR=TRUE AT LINE 1820 AND THE PRINTER IS TURNED OFF BY
5070 REM SETTING VALUE IPRR=FALSE.
5080 REM * PUBLIC DOMAIN SOFTWARE *
5106 L2NH=LEN(B$):FOR ALLF=0 TO L2NH:B2B$=MID$(B$,ALLF+1,1)
5107 IF B2B$=CHR$(8) THEN GOSUB 2720:GOTO 5117
5110 IF LL<>IWT OR B2B$<>CR$ THEN PRINT B2B$; ELSE 5117
5115 IF IPRR THEN LPRINT B2B$;
5117 NEXT ALLF