[VoIP] 2600 Flashing Supervision

[Donald Froula]

I set up a little demo of this at some additional
numbers at my extension:

1-762-0198 plays the flashing 2600 direct, not through
the SF-controlled trunks.

1-762-0199 routes the call through the SF-controlled
trunk group, then to the flashing 2600. The notch
filter action can be heard.

No Blue Box required!

Don

--- Donald Froula <dfroula at sbcglobal.net> wrote:

> I added a flashing 2600 test number to my box at:
> 
> 1-762-2600/2601
> <2600> KP+199+ST
> 
> This number plays back 2600 at .5 second on/.5
> second
> off for 8 seconds, then .25 on/.25 off for another
> 60
> seconds, kind of like the old supervision tests.
> 
> When dialing direct on Asterisk from a local
> extension
> (not through the SF trunk group), it sounds like
> 2600
> Hz. busy and reorder.
> 
> However, when dialing through the SF trunks, one can
> clearly hear the action of the SF notch filter.
> 
> What one hears is a cheep of 2600 when the tone is
> applied, another cheep when the tone is removed, and
> the old warbling noise in-between. The warbling is
> due
> to the rather high level of 2600 and imperfect tone
> filtering of the notch filter.
> 
> This confirms that the cheeps we sometimes hear
> while
> a call completes and supervision is returned through
> ProjectMF are not real winks, but artifacts of the
> tone filter operation.
> 
> Note that the reverse 2600 will not blow off the
> call,
> as I have the near-end trunk group "goodied" through
> the Zaptel settings. However, the notch filters
> still
> work fine, making this observation possible.
> 
> Best,
> 
> Don
> 
> 
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