in usb/tools/ConnectionExerciser/libraries/DTMF/DTMF.cpp [446:470]
byte DTMF_ToneToByte( char tone )
{
byte retVal = 0xFF;
switch (tone)
{
case '0': retVal = 0x0A; break;
case '1': retVal = 0x01; break;
case '2': retVal = 0x02; break;
case '3': retVal = 0x03; break;
case '4': retVal = 0x04; break;
case '5': retVal = 0x05; break;
case '6': retVal = 0x06; break;
case '7': retVal = 0x07; break;
case '8': retVal = 0x08; break;
case '9': retVal = 0x09; break;
case '*': retVal = 0x0B; break;
case '#': retVal = 0x0C; break;
case 'a': retVal = 0x0D; break;
case 'b': retVal = 0x0E; break;
case 'c': retVal = 0x0F; break;
case 'd': retVal = 0x00; break;
}
return retVal;
}