How do I match a "D"? (Was: RE: [Asterisk-Users] In-band disc onn ect problem (legacy PBX) - asterisk doesn't hear the touchtone?)

[David Brodbeck]

> -----Original Message-----
> From: Paul Rodan [mailto:asterisk at glitch.cc]

> I'll ask a stupid question, how does a user hit an alpha 
> letter from his touchtone?
> 
> I know that the Cisco 7960's support entering alpha letters, 
> and it could
> potentially do it (maybe), but how does the average end user 
> enter an a b c or d from their touchtone phone?

They don't.  Most phones lack the fourth column that has those keys.  Some
PBX phones have it, though, and it's common on 2-way radios that include
DTMF keypads.  (Believe it or not, before the advent of cell phones some
businesses provided a "phone patch" interface to allow making phone calls
from their 2-way radios.  This is still quite common in the railroad
industry, AFAIK.)

In my case, I need it because it's how my PBX does disconnect notification
to the voice mail system.  When the line is hung up, it sends a "D".

I expect these digits are very rarely used, which is probably why no one
thought to document that Background() ignores them.