Jasen Betts wrote in a message to All:

 JB> Hi All.

 JB> what does C represent in a dial string?

 JB> my modems generate a tone for the C does anyone know what that tone
 JB> is for? 

Just taking a guess...

Touch-tone standards seem to encompass not 12,  but _16_ keys on the
keypad.  The other four are not commonly found,  and in fact I don't think
I've ever seen them actually,  except in a diagram in a book.  But if they
were there they might perhaps be called A, B, C, and D?

Either that or you have a modem that's interpreting the usual letters that
appear on phone dials.

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