[Asterisk-Users] DTMF A-D

[daryl at introspect.net]

> -----Original Message-----
> From: asterisk-users-admin at lists.digium.com 
> [mailto:asterisk-users-admin at lists.digium.com] On Behalf Of Ken Alker
> Sent: Tuesday, January 20, 2004 1:37 PM
> To: asterisk-users at lists.digium.com
> Subject: [Asterisk-Users] DTMF A-D
> 
[...]
> I've know about DTMF A-D for 20+ years now, but have never 
> heard anyone 
> mention it before, or use it, for that matter (except in old "silver 
> boxing" in the bad ol' days).  Can you elaborate upon how you'd take 
> advantage of DTMF A-D, how you'd produce the tones (are these 
> standard 
> now?), and what exactly you mean by "muting from the far-end"?
[...]

Let me take a crack at this one:
4th column tones have been standard for a very long time, and are often
used for conference control functions.  I have several phones that have
A-D on them.

Which I'm sure is where the original poster would want far-end muting
capability (no need to blast DTMF into a conference call for all to hear
when you are performing control functions on the call).

Whether this is the best way to do things today, especially in hybrid
environments is another discussion.  My personal preference is to see
those nasty things (all in-band signaling, for that matter) die off in
favor of more modern control methods made much more accessible with SIP
phones and large, programmable displays with soft buttons.

Daryl G. Jurbala
BMPC Network Operations
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