I found some really old code today. In the early days of the cellphone before middle schoolers and elementary schoolers had cellphones, the ringtones for Nokia phones were input using an ancient code.

Here’s the zelda theme, which I scrapped off a website a long time ago.

Here’s some MATLAB/OCTAVE code

function nokia2wav (filename, tempo)
Fs = 44.1e3;
if (nargin == 0)
  filename = 'zelda.txt';
end
if (nargin < 2)
  tempo = 125;
end

% read in file and turn it into a long string
fid = fopen(filename);
notebuf = '';
while feof(fid) == 0
   notebuf = [notebuf fgetl(fid)];
end
fclose(fid);

% convert to wav
y = NOKIAtoWAV(notebuf, tempo, Fs);

% write wav file
[buf rem] = strtok(filename, '.');
wavfilename = [buf '.wav'];
wavwrite(y', Fs, wavfilename);

function y = NOKIAtoWAV (str, tempo, Fs)
%NOKIATOWAV converts a string of nokia text into a wavefile
%
% y = NOKIAtoWAV (str, tempo, Fs)
%
% input:
%   str - nokia text string
%   tempo - beats per minute
%   Fs - sampling frequency
%
% output:
%   y - waveform
%

% parse the string to individual NOKIA notes
notes = words(str,',');

% convert each NOKIA note into a frequency and duration
for m = 1:length(notes)
    [midi(m) t(m)] = analyzeNOKIAnote(notes(m,:), tempo);
end

% massage data
midi = midi';
t = t';

% assignment allocation
nend = length(midi);
y = 0;
p = 0;

% keep adding next note to waveform
for n = 1:nend
    y = [y generatenote(MIDItoFreq(midi(n)), t(n), p, Fs)];
    p = asin(y(length(y)));
end

%------------------------------------------------------------------------------
% String Tokenizer
%------------------------------------------------------------------------------

function allWords = words(inputString, delim)
%WORDS parses string by delimiter
%
% allWords = words(inputString, delim)
%
% input:
%   inputString - input string
%   delim - delimiters
% output:
%   allwords - array of parsed strings
%

    remainder = inputString;
    allWords = '';
while (any(remainder))
    [chopped,remainder] = strtok(remainder, delim);
    allWords = strvcat(allWords, chopped);
end

%-------------------------------------------------------------------------------
% Turn NOKIA string into freq and duration
%-------------------------------------------------------------------------------

function [midi t] = analyzeNOKIAnote(str, tempo)
%analyzeNOKIAnote
%
% [midi t] = analyzeNOKIAnote(str, tempo)
%
% input:
%   str - NOKIA note
%   tempo - beats per minute
%
% output:
%   midi - frequency
%   t - duration
%

% split duration and frequency
[duration note] = strtok(str,'abcdefg#-');
t0 = 4*60/tempo;

% compute duration
[duration onehalf] = strtok(duration,'.');
t = t0*1/str2double(duration);
midi = 100;
if(length(onehalf));
    t = 1.5*t;
end

% compute frequency
note = strtrim(note);
if strcmp(note,'c1')
    midi = 60;
elseif strcmp(note,'#c1');
    midi = 61;
elseif strcmp(note,'d1');
    midi = 62;
elseif strcmp(note,'#d1');
    midi = 63;
elseif strcmp(note,'e1');
    midi = 64;
elseif strcmp(note,'f1');
    midi = 65;
elseif strcmp(note,'#f1');
    midi = 66;
elseif strcmp(note,'g1');
    midi = 67;
elseif strcmp(note,'#g1');
    midi = 68;
elseif strcmp(note,'a1');
    midi = 69;
elseif strcmp(note,'#a1');
    midi = 70;
elseif strcmp(note,'b1');
    midi = 71;
elseif strcmp(note,'c2');
    midi = 72;
elseif strcmp(note,'#c2');
    midi = 73;
elseif strcmp(note,'d2');
    midi = 74;
elseif strcmp(note,'#d2');
    midi = 75;
elseif strcmp(note,'e2');
    midi = 76;
elseif strcmp(note,'f2');
    midi = 77;
elseif strcmp(note,'#f2');
    midi = 78;
elseif strcmp(note,'g2');
    midi = 79;
elseif strcmp(note,'#g2');
    midi = 80;
elseif strcmp(note,'a2');
    midi = 81;
elseif strcmp(note,'#a2');
    midi = 82;
elseif strcmp(note,'b2');
    midi = 83;
elseif strcmp(note,'-');
    midi = 0;
else
    note;
end
midi = midi;

function f = MIDItoFreq(MIDInum)
%MIDItoFreq gets the frequency of a MIDI note number
%
%   f = MIDItoFreq(MIDInum)
%
%   input:
%       MIDInum - MIDI note number
%
%   output:
%       f - frequency of MIDI note number
%

f = 440*(2^(1/12).^(MIDInum-69));

function y = generatenote(f, t, p, Fs)
%generatenote generates a wav of a certain frequency and duration
%
%   y = generatenote(f, t, p, Fs)
%
%   input:
%       f - frequency
%       t - duration
%       p - phase shift
%       Fs - sampling frequency (usually 44.1 kHz for audio)
%
%   output:
%       y - waveform
%

% t in seconds
t = 0:Fs*t;
y = sin(2*pi*f/Fs*t+p);
% add fade to eliminate pops
x0 = round(10e-3*Fs);
y(end-x0+1:end) = y(end-x0+1:end).*linspace(1,0,x0);