REM FILE: DTMF2PRN.BAS, WRITTEN IN QBASIC, by Paul Bergsman
REM
REM Inputs 4-bit data from an M8870, DTMF Receiver to Binary converter,
REM via an IBM-compatible Parallel Printer Port. Output from the
REM M8870 is read into the parallel port's (Base Address + 1). D6
REM of the (Base Address + 1), the ACKbit, is used to input M8870's
REM strobe signal. When D6 goes to an active HIGH, the new byte value is
REM displayed on the screen. The ACK bit can also be used as a hardware
REM TSR, (Terminate and Stay Resident), input. If some additional
REM software is added, this circuit can be operated as a TSR device.
REM The program opens a file on Disk Drive "A:\". All files begin with
REM "DTMF", followed by four digits coding today's date. For example, if
REM today's date is 12/23/1994, the program opens a file titled:
REM DTMF1223.DAT
REM All DTMF signals decoded on 12/23, will be stored in the file
REM called DTMF1223. Each record in the file will start with the time
REM the phone was taken off-hook, followed by all DTMF codes, and
REM ending with the time of hang-up. The file will include a "P" for a
REM pause greater than 10 seconds. If the pause is longer than two
REM minutes, the program closes the current record and waits for an
REM off-hook signal to start a new record.
REM
REM Each day starts a new file. If operating at midnight the program
REM closes the current file and opens a new one for the new date.
REM
REM To EXIT the program, press "E"
REM
REM The following IC chips are equivalent:
REM CMD CM8870C, Crystal CS8870, Motorola MC8870, and Teltone M8870
REM
OpenFile:
	FileName$ = DATE$
	FileName$ = "DTMF" + LEFT$(FileName$, 2) + MID$(FileName$, 4,2) + ".DAT"
	FileName$ = "A:\" + FileName$
	OPEN FileName$ FOR APPEND AS #1: REM add records to today's file
	INPUTBITS = 0: ActiveTone = 0: OffHook =  0: TonePresent = 0:
	D0  = 1: D1 = 1: D6 = 64: LptPortAddress = 0: PhoneNumber$ = ""
	LptPortAddress = 888:  REM Base address of Graphic Card's printer port.
                           REM Use 632 for 3ED printer port base address.
                           REM Use 956 for Monochrome Card's printer port.
	CLS
	Today$ = DATE$
	PRINT "Open file = "; FileName$

WaitForCall:
	OffHook = INP(LptPortAddress + 1)
	IF Today$ <> DATE$ THEN GOTO CloseFile: REM new day means new file
	Ch$ = INKEY$
	IF (Ch$ = "e") OR (Ch$ = "E") THEN GOTO ExitProgram:
	IF (OffHook AND D0) = 0 THEN GOTO WaitForCall:    REM phone off-hook?
	REM start new record
	StartTime& = TIMER
	PhoneNumber$ = TIME$ + " ": REM record begins with start time

WaitForDTMFcode:
	StartTime& = TIMER
	OUT (LptPortAddress + 2), 4: REM set all bits HIGH with 000001100
	TonePresent = INP(LptPortAddress + 2): REM is a DTMF tone present
	OffHook = INP(LptPortAddress + 1)
	IF (OffHook AND D0) = 0 THEN GOTO DigestDTMFcode:
	EndTime& = TIME&: ElapsedTime& = EndTime& - StartTime&
	IF (ElapsedTime& > 120) THEN GOTO CloseFile:
	IF (ElapsedTime& > 10) AND  (RIGHT$(PhoneNumber$, 2) <> "P ") THEN PhoneNumber$ = PhoneNumber$ + "P "
	END IF

DigestDTMFcode:
	IF (TonePresent AND DO) = 0 THEN GOTO WaitForDTMFcode:
	ActiveTone = INP(LptPortAddress + 1): REM input decoded Touch-Tones
	REM  -=[ reformat raw data as low nibble, D0 - D3 J=-
	ActiveTone = ActiveTone XOR 128: REM invert the inverted bit,  D7
	IF (ActiveTone AND 128) = 128 THEN ActiveTone = ((ActiveTone - 128) * 2) + 128
    GOTO Shift5Right:
	ELSE
	ActiveTone = ActiveTone * 2:
	END IF

Shift5Right: 
	ActiveTone = ActiveTone \ 16:

AddToneToRecord:
	SELECT CASE ActiveTone
	CASE 1 TO 9
      Temp$ = STR$ (ActiveTone): REM decode characters "1" TO "9"
    CASE  10
      Tenp$ = "0"
    CASE 11
      Temp$ = "*"
    CASE 12
      Temp$ = "#"
    CASE 13 TO 15
      Temp$ = STRS$ (ActiveTone + 53): REM decode characters "A" TO "C"
	CASE 0
      Temp$ = "D"
	END SELECT

	PhoneNumber$ = PhoneNumber$ + Temp$ + " "
    PRINT Temp$; " "; : REM display DTMF code
	OUT (LptPortAddress + 2), 4: REM set all bits HIGH with 00000100
	IF (INP(LptPortAddress + 2) AND D1) = 0 THEN GOTO SaveRecord:
	OffHook = INP(LptPortAddress + 1): REM is phone still off hook?
	IF (OffHook AND DO) = 0 THEN GOTO WaitForDTMFcode:
    PRINT

SaveRecord:
	Temp$ = Temp$ + TIME$: REM add hang-up time to file
	PRINT #1, Temp$: REM save record to file
	PRINT Temp$: PRINT: REM display record
	GOTO WaitForDTMFcode:

CloseFile:
	CLOSE
	GOTO OpenFile:

ExitProgram:
	CLOSE
	END