Filter
InString
KeyInput
ModemInput
	BackSpace
LineFeed
 Set screen color.
 Value returned by INKEY$
 when ALT+q is pressed.t
 Set up prompt on bottom line of screen and turn cursor on:
Press ALT+q to quit"
 Print between lines 1 & 23.
 Open communications (1200 baud, no parity, 8-bit data, 
 1 stop bit, 256-byte input buffer):
COM1:1200,N,8,1"d
 Main communications loop.
 Check the keyboard.
 Exit the loop if the user
 pressed ALT+q. 
 Otherwise, if the user has
 pressed a key, send the
 character typed to the modem.
 Check the modem. If characters are waiting (EOF(1) is
 true), get them and print them to the screen:
 LOC(1) gives the number of characters waiting:
 Filter out line feeds and
 backspaces, then print.
 End communications.
Filter
= FILTER 
 Filters characters in an input string.i
 Look for backspace characters and recode them to=
 CHR$(29) (the LEFT cursor key):
 Look for line-feed characters and remove any found: