MS CODE 11025 Hz will be the audio sample rate. The three tones will be 11025/18=612.5 Hz, 11025/9=1225 Hz, and 11025/6=1837.5 Hz. All these tones are in the normal SSB passband. The baud rate is 612.5. Tone 1 is 612.5 Tone 2 is 1225 Tone 3 is 1837.5 To have instant character sync we have a two bit idle using tone 2 for each character. This is like psk31. So the AFC works faster and better each character will have an average frequency of the idle tone 2. This means each code has equal number of bits using tone 1 and tone 3. 8 bits of either tone 1 or tone 3 give 70 combinations. It takes 36 characters for MS. Here are the codes. space 2211113333 1 15 A 2211131333 2 23 B 2211133133 3 27 C 2211133313 4 29 D 2211133331 5 30 E 2211311333 6 39 F 2211313133 7 43 G 2211313313 8 45 H 2211313331 9 46 I 2211331133 10 51 J 2211331313 11 53 K 2211331331 12 54 L 2211333113 13 57 M 2211333131 14 58 N 2211333311 15 60 O 2213111333 16 71 P 2213113133 17 75 Q 2213113313 18 77 R 2213113331 19 78 S 2213131133 20 83 T 2213131313 21 85 U 2213131331 22 86 V 2213133113 23 89 W 2213133131 24 90 X 2213133311 25 92 Y 2213311133 26 99 Z 2213311313 27 101 0 2213311331 28 102 1 2213313113 29 105 2 2213313131 30 106 3 2213313311 31 108 4 2213331113 32 113 5 2213331131 33 114 6 2213331311 34 116 7 2213333111 35 120 8 2231111333 36 135 9 2231113133 37 139 2231113313 38 141 2231113331 39 142 2231131133 40 147 2231131313 41 149 2231131331 42 150 2231133113 43 153 2231133131 44 154 2231133311 45 156 2231311133 46 163 2231311313 47 165 2231311331 48 166 2231313113 49 169 2231313131 50 170 2231313311 51 172 2231331113 52 177 2231331131 53 178 2231331311 54 180 2231333111 55 184 2233111133 56 195 2233111313 57 197 2233111331 58 198 2233113113 59 201 2233113131 60 202 2233113311 61 204 2233131113 62 209 2233131131 63 210 2233131311 64 212 2233133111 65 216 2233311113 66 225 2233311131 67 226 2233311311 68 228 2233313111 69 232 2233331111 70 240 Regards, Jim FitzSimons W7ANF