Dial generates the dtmf tone signals used for telephone
dialing and by default sends the signals to stdout.
The output can be piped directly into aplay - to play the DTMF.
Usage: Usually you just run need to give the phone number that you wish to dial as an argument.
# Local usage:
$ dial 555-3456 | aplay -
# Docker usage
$ docker build -t dial .
$ docker run --rm dial 555-3456 | aplay -
By default the tone generated for each dialed digit is 100 milliseconds. Silence between digits is 50 milliseconds. A comma or a blank space between digits is replaces with a 500 milliseconds delay.
The duration values can be set by these arguments: --tone-time milliseconds (default 100) --silent-time milliseconds (default 50) --sleep-time milliseconds (default 500)
By default the output is sent to stdout. Generated samples are 8 bits unsigned values (AFMT_U8). 8000 samples/second.
To send the output to another device one can use the option:
--output-dev device (default -)
This option can be used also to store raw audio samples to a file, or to stdout. Use the file name with the --output-dev option, or a simple "-" to sent to stdout. If the output device is not the sound special file then another option should be used to eliminate attempts to set the sound driver parameters:
--use-audio onoff (default 0)
Use "--use-audio 1" to enable sound ioctls.
It is possible to generate the samples in AFMT_S16_LE format, To do that use the option:
--bits bits-per-sample (default 8)
8 will generate AFMT_U8 format, 16 will generate AFMT_S16_LE format.
It is possible to generate samples in a different sampling rate. To do that use the option:
--speed sampling-rate (default 8000)
Sound samples are generated by sub-sampling values from a cosine table. By default the cosine table contains 256 samples. Smaller cosine table sizes still produce the correct frequencies but with some distortion. These options can be used:
--table-size size (default 256)
The table used is of a different size
--volume volume (default 100)
Values stored in the table are scaled down volume/100 times the maximum value which does not cause overflow on the 8 or 16 bit samples.
To generate a stereo sound use the options --right or --left. By default they are 0 and a mono sample is generated. If any of these option are 1, a stereo sample will be generated and the corresponding channel will be turned on.
(C) 1998 Itai Nahshon, nahshon@actcom.co.il
Use and redistribution are subject to the GNU GENERAL PUBLIC LICENSE v2.