16c84 PIN
                    11  10  9   8   7   6
 TONE  FREQ        RB5 RB4 RB3 RB2 RB1 RB0
 000  1750 Eu Tone  0   0   0   0   0   0
 001   67.0         0   0   0   0   0   1
 002   69.4 *       0   0   0   0   1   0
 003   71.9         0   0   0   0   1   1
 004   74.4         0   0   0   1   0   0
 005   77.0         0   0   0   1   0   1
 006   79.7         0   0   0   1   1   0
 007   82.5	    0   0   0   1   1   1 
 008   85.4	    0   0   1   0   0   0 
 009   88.5	    0   0   1   0   0   1 
 010   91.5	    0   0   1   0   1   0 
 011   94.8	    0   0   1   0   1   1 
 012   97.4	    0   0   1   1   0   0 
 013  100.0	    0   0   1   1   0   1 
 014  103.5	    0   0   1   1   1   0 
 015  107.2	    0   0   1   1   1   1  
 016  110.9	    0   1   0   0   0   0 
 017  114.8	    0   1   0   0   0   1 
 018  118.8	    0   1   0   0   1   0 
 019  123.0	    0   1   0   0   1   1 
 020  127.3	    0   1   0   1   0   0 
 021  131.8	    0   1   0   1   0   1 
 022  136.5	    0   1   0   1   1   0 
 023  141.3         0   1   0   1   1   1
 024  146.2         0   1   1   0   0   0
 025  151.4         0   1   1   0   0   1
 026  156.7         0   1   1   0   1   0
 027  159.8 *       0   1   1   0   1   1
 028  162.2         0   1   1   1   0   0
 029  165.5 *       0   1   1   1   0   1
 030  167.9         0   1   1   1   1   0
 031  171.3 *       0   1   1   1   1   1
 032  173.8         1   0   0   0   0   0
 033  177.3 *       1   0   0   0   0   1
 034  179.9         1   0   0   0   1   0   * Indicates NON EIA standard Tone
 035  183.5 *       1   0   0   0   1   1
 036  186.2         1   0   0   1   0   0
 037  189.9 *       1   0   0   1   0   1
 038  192.8         1   0   0   1   1   0
 039  196.6 *       1   0   0   1   1   1
 040  199.5 *       1   0   1   0   0   0
 041  203.5         1   0   1   0   0   1
 042  206.5 *       1   0   1   0   1   0
 043  210.7         1   0   1   0   1   1
 044  218.1         1   0   1   1   0   0
 045  225.7         1   0   1   1   0   1
 046  229.1 *       1   0   1   1   1   0
 047  233.6         1   0   1   1   1   1
 048  241.8         1   1   0   0   0   0
 049  250.3         1   1   0   0   0   1
 050  254.1 *       1   1   0   0   1   0
 051  255   *       1   1   0   0   1   1
 052  1Khz TEST     1   1   0   1   0   0
 053  1800 Eu Tone  1   1   0   1   0   1
 054  1200 Packet   1   1   0   1   1   0
 055  2200 Packet   1   1   0   1   1   1
 056  800   *       1   1   1   0   0   0
 057  900   *       1   1   1   0   0   1
 058  1100  *       1   1   1   0   1   0
 059  1300  *       1   1   1   0   1   1
 060  1500  *       1   1   1   1   0   0
 061  2000  *       1   1   1   1   0   1
 062  2500  *       1   1   1   1   1   0
 063  3500  *       1   1   1   1   1   1





		All CTCSS tones are within EIA standard of .08% .
   		Use a 4Mhz crystal with 2x18pF capacitors. 
		PTT line is active LOW. PTT is RB7 Pin 13.
		OUTPUT tone is on RA2 Pin1 ,see Low pass filter diag.
		Lines RB0-RB5 can be fitted with DIP switches to set
		tone frequencies as per table above. A 1 on the table
		indicates the RB pin is logic HI . All RB port pins have
		been programmed with internal pullup resistors and will
		float HI if left open. The binary inputs are read only on
		power up and not each time the PTT is keyed.

		For CTCSS tones use a Low pass filter as shown here as the
		output waveform is square. RO is an padding resistor to
		allow for level adjustment typically 20k.


		RA2--------2k2----------RO----Output
		Pin1		  |
				  |
				  1uF
				  |
				  GND


		Philips FM900 hints:
  
			     You can find a  suitable PTT signal at
		SK403 pin 6 or  switch it yourself manually or just
		connect the PTT input to ground perminently.
		Use a 2Meg resistor for RO and inject at U301 pin 9
		Both of these locations are on the Synth/Control
		board of the FM900.