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RTX Format

What is RTX ?

RTX stands for Extended Ringtone Format.

It is a simple text-based format used to create ringtones that can be uploaded to a mobile phone. Most cellphone manufacturers support RTX. RTX is a backwards compatible extension of RTTTL You can find a example of a RTX ringtone below:


The Format Specification

A RTX ringtone can be devided into 3 parts, which are separated using a colon:

  • The title.
  • Default parameters, like: default duration, pitch and bpm.
  • The actual songdata.
The title

The title of the song, it can have no more than 10 characters.

The title of the song in the example above is 'Muppets'

Default parameters

The following parameters are supported in this section:

d Default duration
o Default octave
b Default bpm (beats per minute)
l Looping (number of times the song is repeated)
s Default style

If these parameters are not specified, the following values will be used:

Duration: 4, Scale: 6 and BPM: 63 ( :d=4;o=6;b=63: )

The following values are valid for the duration parameter:

1 a full note
2 a half note
4 a quarter note
8 an eighth note
16 a sixteenth note
32 a thirty-second note

The following values are valid for the octave parameter:

5 Note A is 440Hz
6 Note A is 880Hz
7 Note A is 1760Hz
8 Note A is 3520Hz

The following values are valid for the style parameter:

N Natural
C Continuous
S Staccato

The following values are valid for the looping parameter:

0 No looping
1-14 Loop n times
15 Loop infinite

The default BPM can be one of the following values:

25, 28, 31, 35, 40, 45, 50, 56, 63, 70, 80, 90, 100, 112, 125, 140,
160, 180, 200, 225, 250, 285, 320, 355, 400, 450, 500, 565, 635, 715, 800 and 900.

The songdata

The last section of the string contains the actual songdata.

All the notes are separated by a comma. The notes are encoded as follows:

[duration] note [scale] [special-duration],[duration] note [scale] [special-duration], etc...

If the optional values 'duration' and/or 'scale' are left blank, the default parameters from the second section of the RTX string are used.

The following notes can be used in a RTX string:

P Pause
C Note C
C# Note Cis
D Note D
D# Note Dis
E Note E
F Note F
F# Note Fis
G Note G
G# Note Gis
A Note A
A# Note Ais
H Note H


8f#5 1/8th Note Fis, Octave 5
8d5 1/8th Note D, Octave 5
8p 1/8th Pause
c5 Default length, Note C, Octave 5
8d 1/8th Note D, Default octave

How to send a RTX ringtone to a mobile phone ?

To send a RTX ringtone to a mobile phone, it first has to be encoded and compressed before it is send to the mobile phone as 8 bit data.

You can find SMS software to send RTX ringtones here.