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Dunno if this will help, It's in C but you might be able to convert it into perl.
/* * detect.c * This program will detect MF tones and normal * dtmf tones as well as some other common tones such * as BUSY, DIALTONE and RING. * The program uses a goertzel algorithm to detect * the power of various frequency ranges. * * input is assumed to be 8 bit samples. The program * can use either signed or unsigned samples according * to a compile time option: * * cc -DUNSIGNED detect.c -o detect * * for unsigned input (soundblaster) and: * * cc detect.c -o detect * * for signed input (amiga samples) * if you dont want flushes, -DNOFLUSH * * Tim N. */ #include <stdio.h> #include <math.h> #include "detect.h" /* * calculate the power of each tone according * to a modified goertzel algorithm described in * _digital signal processing applications using the * ADSP-2100 family_ by Analog Devices * * input is 'data', N sample values * * ouput is 'power', NUMTONES values * corresponding to the power of each tone */ calc_power(data,power) #ifdef UNSIGNED unsigned char *data; #else char *data; #endif float *power; { float u0[NUMTONES],u1[NUMTONES],t,in; int i,j; for(j=0; j<NUMTONES; j++) { u0[j] = 0.0; u1[j] = 0.0; } for(i=0; i<N; i++) { /* feedback */ #ifdef UNSIGNED in = ((int)data[i] - 128) / 128.0; #else in = data[i] / 128.0; #endif for(j=0; j<NUMTONES; j++) { t = u0[j]; u0[j] = in + coef[j] * u0[j] - u1[j]; u1[j] = t; } } for(j=0; j<NUMTONES; j++) /* feedforward */ power[j] = u0[j] * u0[j] + u1[j] * u1[j] - coef[j] * u0[j] * u1[j] +; return(0); } /* * detect which signals are present. * * return values defined in the include file * note: DTMF 3 and MF 7 conflict. To resolve * this the program only reports MF 7 between * a KP and an ST, otherwise DTMF 3 is returned */ decode(data) char *data; { float power[NUMTONES],thresh,maxpower; int on[NUMTONES],on_count; int bcount, rcount, ccount; int row, col, b1, b2, i; int r[4],c[4],b[8]; static int MFmode=0; calc_power(data,power); for(i=0, maxpower=0.0; i<NUMTONES;i++) if(power[i] > maxpower) maxpower = power[i]; /* for(i=0;i<NUMTONES;i++) printf("%f, ",power[i]); printf("\n"); */ if(maxpower < THRESH) /* silence? */ return(DSIL); thresh = RANGE * maxpower; /* allowable range of powers */ for(i=0, on_count=0; i<NUMTONES; i++) { if(power[i] > thresh) { on[i] = 1; on_count ++; } else on[i] = 0; } /* printf("%4d: ",on_count); for(i=0;i<NUMTONES;i++) putchar('0' + on[i]); printf("\n"); */ if(on_count == 1) { if(on[B7]) return(D24); if(on[B8]) return(D26); return(-1); } if(on_count == 2) { if(on[X1] && on[X2]) return(DDT); if(on[X2] && on[X3]) return(DRING); if(on[X3] && on[X4]) return(DBUSY); b[0]= on[B1]; b[1]= on[B2]; b[2]= on[B3]; b[3]= on[B4]; b[4]= on[B5]; b[5]= on[B6]; b[6]= on[B7]; b[7]= on[B8]; c[0]= on[C1]; c[1]= on[C2]; c[2]= on[C3]; c[3]= on[C4]; r[0]= on[R1]; r[1]= on[R2]; r[2]= on[R3]; r[3]= on[R4]; for(i=0, bcount=0; i<8; i++) { if(b[i]) { bcount++; b2 = b1; b1 = i; } } for(i=0, rcount=0; i<4; i++) { if(r[i]) { rcount++; row = i; } } for(i=0, ccount=0; i<4; i++) { if(c[i]) { ccount++; col = i; } } if(rcount==1 && ccount==1) { /* DTMF */ if(col == 3) /* A,B,C,D */ return(DA + row); else { if(row == 3 && col == 0 ) return(DSTAR); if(row == 3 && col == 2 ) return(DPND); if(row == 3) return(D0); if(row == 0 && col == 2) { /* DTMF 3 conflicts with MF 7 */ if(!MFmode) return(D3); } else return(D1 + col + row*3); } } if(bcount == 2) { /* MF */ /* b1 has upper number, b2 has lower */ switch(b1) { case 7: return( (b2==6)? D2426: -1); case 6: return(-1); case 5: if(b2==2 || b2==3) /* KP */ MFmode=1; if(b2==4) /* ST */ MFmode=0; return(DC11 + b2); /* MF 7 conflicts with DTMF 3, but if we made it * here then DTMF 3 was already tested for */ case 4: return( (b2==3)? D0: D7 + b2); case 3: return(D4 + b2); case 2: return(D2 + b2); case 1: return(D1); } } return(-1); } if(on_count == 0) return(DSIL); return(-1); } read_frame(fd,buf) int fd; char *buf; { int i,x; for(i=0; i<N; ) { x = read(fd, &buf[i], N-i); if(x <= 0) return(0); i += x; } return(1); } /* * read in frames, output the decoded * results */ dtmf_to_ascii(fd1, fd2) int fd1; FILE *fd2; { int x,last= DSIL; char frame[N+5]; int silence_time; while(read_frame(fd1, frame)) { x = decode(frame); /* if(x== -1) putchar('-'); if(x==DSIL) putchar(' '); if(x!=DSIL && x!=-1) putchar('a' + x); fflush(stdout); continue; */ if(x >= 0) { if(x == DSIL) silence_time += (silence_time>=0)?1:0 ; else silence_time= 0; if(silence_time == FLUSH_TIME) { fputs("\n",fd2); silence_time= -1; /* stop counting */ } if(x != DSIL && x != last && (last == DSIL || last==D24 || last == D26 || last == D2426 || last == DDT || last == DBUSY || last == DRING) ) { fputs(dtran[x], fd2); #ifndef NOFLUSH fflush(fd2); #endif } last = x; } } fputs("\n",fd2); } main(argc,argv) int argc; char **argv; { FILE *output; int input; input = 0; output = stdout; switch(argc) { case 1: break; case 3: output = fopen(argv[2],"w"); if(!output) { perror(argv[2]); return(-1); } /* fall through */ case 2: input = open(argv[1],0); if(input < 0) { perror(argv[1]); return(-1); } break; default: fprintf(stderr,"usage: %s [input [output]]\n",argv[0]); return(-1); } dtmf_to_ascii(input,output); fputs("Done.\n",output); return(0); }

In reply to Re: Parsing touch tone input? by Anonymous Monk
in thread Parsing touch tone input? by TacoVendor

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