On 8/25/2018 8:06 AM, Paul wrote:
philo wrote:
My service went out and AT&T ran a diagnostic and said my router went
out and they would send a new one. While waiting I decided to try my
router at a neighbor's house who also has AT&T broadband and it worked
OK there so I called them back and they will eventually send a tech
out to repair the line.

At the wires coming into my house I only got a reading of 2mv ac

I know back in the days of landline and DSL the voltage should have
been 48vdc as best as I recall...however I don't know what a normal
voltage would be for broadband. Anyone here have that knowledge?

Thanks


Fortunately I can tether my machine to my smartphone to post this.

http://www.dslreports.com/forum/r412...for-DSL-to-run


Â*Â* "Since ADSL can be deployed on a dry pair with no DC bias whatsoever,
Â*Â*Â* it's not too surprising that it shows so low."

If POTS service has specifically been removed, there's
no reason for -48V to be on the line. Neither would
you expect the occasional 180VAC at 25Hz for ringing
voltage.

If you had combo service, the "phone filter" passes DC to 8KHz
to the phone. The ADSL needs the 25KHz or higher part. The phone
filter is necessary, so the higher frequency signals don't
alias down into the voice band.

ADSL starts at 25KHz and extends upwards (1.5MHz or higher).
It depends on the standard involved, as to how high the
highest frequency is.

You expect the launch amplitude to be significant,
because the line loss could be 50dB or more by the time
it gets to the other end. When you have a pedestal at the
corner serving ADSL, then not as much signal might be
needed (the box may not be designed to drive 18000 feet
of wire, but designed for a shorter max distance).

https://www.eetimes.com/document.asp?doc_id=1224781

Â*Â* "Assuming a line impedance of 100 ohms, the resulting
Â*Â*Â* RMS voltage is 3.31 volts and the RMS current is 33 mA."

And notice they're using transformers and differential
circuits for it too. Wouldn't be good for DC to be
shoved through the transformer (saturation issue).

That article was written in the year 2000.

I no longer have a "convenient" access point, to take
a reading off the line hot. The demarc used to use those
nice brass screw terminals, and I could take a reading
off that easily. When the installer came in, he defeated
my easy access point. Now, I'd need to get into the
RJ11 junction box to take a reading.

Â*Â* Paul


I have all the tools I need to get to the AT&T input and there is no
voltage there either dc or ac (other than a tiny stray voltage one could
expect being picked up on a long wire run)

Thank you for confirming my suspicion that there should be at least a
few volts there.

My frequency meter died years ago and I have no justification for
replacing it.

BTW: It is very sad that AT&T now has terrible service, they won't get
here until Thursday. When I had a problem two years ago from the time I
called until the time they came out and had it all fixed was 90 minutes.

I spent more time than that just on the phone.