Hi Adam,
I hooked up an ADSL modem yesterday and found that it's putting out 3 
frequencies simultaneously with a cadence of about 1.5 secs on, 1.5 secs 
off.

As you say, the three tones seem to be required to cover all ADSL 
variants. I've not measured them exactly yet, but in the spectrum mode 
on my Bitscope, they appear to be roughly 39KHz, 72KHz and 107KHz.

Some of the documents I've found mention the tones "change phase every 
16ms" but I don't really know what that means in this context.

I'll see if the standard is not too expensive. Hopefully it contains the 
details I need.
David...

M. Adam Davis wrote:
> The phrase you'r looking for is "ADSL handshake" - this is the process
> where the modem makes itself known and attempts to locate the dslam.
>   
-- 

___________________________________________
David Duffy        Audio Visual Devices P/L
Unit 8, 10 Hook St, Capalaba 4157 Australia
Ph: +61 7 38235717      Fax: +61 7 38234717
Our Web Site: www.audiovisualdevices.com.au
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