DTMF/Musical tones before a radio transmission?
 

In the area I am in--on frequency 151.1900 (CDF/Cal Fire dispatch, Monte
Vista), sometimes a radio transmission will be preceded by several DTMF
tones (touch-tone phone button tones). On other occasions, a radio
transmission will be preceded by two musical tones, about 1 second each,
with the first tone being higher than the second tone, almost sounds like
high pitched fog-horn type tones.

Is there any significance to this?

DTMF/Musical tones before a radio transmission?
 

On Dec 4, 4:57 am, "Daniel W. Rouse Jr."
wrote:
In the area I am in--on frequency 151.1900 (CDF/Cal Fire dispatch, Monte
Vista), sometimes a radio transmission will be preceded by several DTMF
tones (touch-tone phone button tones). On other occasions, a radio
transmission will be preceded by two musical tones, about 1 second each,
with the first tone being higher than the second tone, almost sounds like
high pitched fog-horn type tones.

Is there any significance to this?

Check this link:
http://en.wikipedia.org/wiki/Selective_calling

The site has some sample audio files you can compare with.

-Bill

DTMF/Musical tones before a radio transmission?
 

"Bill" wrote in message
...
On Dec 4, 4:57 am, "Daniel W. Rouse Jr."
wrote:
In the area I am in--on frequency 151.1900 (CDF/Cal Fire dispatch, Monte
Vista), sometimes a radio transmission will be preceded by several DTMF
tones (touch-tone phone button tones). On other occasions, a radio
transmission will be preceded by two musical tones, about 1 second each,
with the first tone being higher than the second tone, almost sounds like
high pitched fog-horn type tones.

Is there any significance to this?

Check this link:
http://en.wikipedia.org/wiki/Selective_calling

The site has some sample audio files you can compare with.
....

A more technical better page (also with a few examples)
http://www.genave.com/two-tone_paging.htm

and a nice reference chart
http://www.midians.com/pdf/tone_signaling.pdf

DTMF/Musical tones before a radio transmission?
 

"Daniel W. Rouse Jr." wrote in
:

In the area I am in--on frequency 151.1900 (CDF/Cal Fire dispatch, Monte
Vista), sometimes a radio transmission will be preceded by several DTMF
tones (touch-tone phone button tones). On other occasions, a radio
transmission will be preceded by two musical tones, about 1 second each,
with the first tone being higher than the second tone, almost sounds
like high pitched fog-horn type tones.

Is there any significance to this?




Sure!!! The DTMF tones are probably used to access parts of the system on
an as neede basis eg a normally off repeater that has dialup access The
othere tones are used for Fire Pagers These a usually carried by Volunteer
Firemen in rural areas. The dispatcher can pager the firemen by sending a
unique tine pattern that unlcoks the squelch in a specific fire department
Those tone are usually followed by an announcement eg "Attention Podunk
fire department, please respond to a fire alarm at civic address xxxyyyyy
please acknowledge receipt of this page Operator qq K.

At least thats what they are used for here :)

Hope it helps



--
Panzer

DTMF/Musical tones before a radio transmission?
 

On Mon, 3 Dec 2007 15:57:46 -0800, "Daniel W. Rouse Jr."
wrote:

In the area I am in--on frequency 151.1900 (CDF/Cal Fire dispatch, Monte
Vista), sometimes a radio transmission will be preceded by several DTMF
tones (touch-tone phone button tones). On other occasions, a radio
transmission will be preceded by two musical tones, about 1 second each,
with the first tone being higher than the second tone, almost sounds like
high pitched fog-horn type tones.

DTMF could be used for:

Auto Number Identification - ANI
Activate remote tx or rx sites

The second set is most likely paging in the two tone format.

See the following for more info:

http://www.wpascanner.com/wiki/index...dwaTone_Out


http://www.wpascanner.com/wiki/index.php?title=Tones


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