Wrt to what you may have intended to ask someone else, Power in relation to ADSLx and FTTC is reported in the following form:;

.                Down            Up
SNR (dB):        6.2             6.2
Attn(dB):        19.6            0.0
Pwr(dBm):        13.6            7.4

Wiki dBm.

I was picking up on the OP's original reference to power-

"
As an alternative explanation I was wondering if DLM may see my line as particularly stable on the original high TX power.
Could it then instruct the DSLAM to reduce this power in stages to help reduce the crosstalk from my line on to others in the same bundle?
"

And wondering given the constraints of voltage levels on the PSTN, whether it truly is "power" in the conventional sense; or some other means.

I am hoping that yourself or anyone else with the technical knowledge of that part of the broadband system would be able to clarify.

In reply to a post by PhilipD:

Hi

Yes power can change. I saw that on my new FTTC connection, started off at 11db SNR and 13.3db transmit power to me, and an overnight re-sync on the 1st night saw the transmit power drop by 1db and SNR down to 10.6db.

Reducing power is a crosstalk preventative measure and also helps prevent echos back up the line, and if you have plenty of margin, it makes sense to reduce the power.

Regards

Phil

Thanks Phil. Sounds like this is what has happened to me (twice).
I expect the DLM system monitors the error rate after the reduction in power to confirm it has not suffered unduly.
For me the second reduction in SNR margin occurred about a week after the first.

I just hope that the power will be increased again if crosstalk reduces my SNRM.

Think I'm going to have to get a DrayTek to see this data. Do these show power by tone?