Hi, John:

0)    Allow me to share some old-fashioned telephony line-man tricks, kind of trade-secretes. 😉

1)     "Analog phones can not be detected unless they're off hook ...    ":

    This is true only if your measurement capability is limited within the pure DC (Direct Current) domain. A tiny step outside of it will open up some possibilities. As we all know, a POTS (Plain Old Telephone Set) in OnHook state will ring when Ringing Signals are applied from the serving telephone switch. This is because there is a Ringer Circuit always connected across the Tip-Ring pair of the subscriber loop wire pair. The basic component of a Ringer is an electro-mechanical device that appears as an inductor (L) on the electrical side and functions as a hammer on the mechanical side. To prevent the L from constantly drawing 48VDC battery current, a series capacitor (C) has to be included. Consequently, AC (Alternate Current) signals are used to activate the Ringer. Depending on the country, this AC frequency is around 16 - 20 Hz. So, the Ringer Circuit is designed as a series L-C resonator that appears as a resistive load at that chosen frequency. There is a range of  L & C combination values that can be used for this purpose. Practically, C comes out to be around 1uF (One Micro-Farad) and rated at least 250VAC to survive the voltage swing of the Ringing Signal. Accordingly, there are ways to detect a POTS by measuring its L or C, but not by a pure DC approach.

2)    " ...  between sitting idle or the cables cut.   ":

    Inductance measurements are generally more involved. So, treating an OnHook POTS as a capacitor is a simpler way for the current purpose. There are a couple possible techniques. For example:

    A.    A line-man can put a voltmeter across a subscriber loop wire pair to verify that it is being energized by the 48VDC battery from the CO (Central Office), and is not shorted or leaking. Upon disconnecting one wire of the pair from the CO side, if the voltmeter reading drops to zero right away, the loop is an open loop (without a POTS). If its reading maintains for awhile (actually, a fairly long time), there is at least one POTS (1uF or equivalent) on the line. 

    B.    A "Battery Reversal Tester" can be used in the CO to actually measure how much charge is stored at the end of a subscriber loop, by observing the length of time that a subscriber line voltage takes to reverse upon flipping the polarity of the 48VDC battery voltage applied to it. This is done through controlled known discharge circuit, based on RC time-constant.

    C.    With a "calibrated" Battery Reversal Tester, the CO craftsman can tell how many POTS are plugged into the jacks along a subscriber loop. That is, the more POTS are plugged in, the longer it takes to reverse the voltage on the subscriber side. This is where the REN (Ringer Equivalent Number) on the POST label comes from. For example, when a subscriber complains that ringing is too weak, the CO can tell whether that subscriber has too many phones plugged in, even without a physical visit. The convention established by FCC is 5 REN (or about 5uF) - Maximum number of ringers (POTS) for the subscriber and minimum Ringing Signal capability for the CO.

    D.    A seasoned line-man can do Step C. on the pole by himself, even without the support of the CO instrumentation, using everyday VOM (Volt-Ohm-MiliAmper) meter which is in his basic tool kit.

Hope this helps.


Happy Holidays!


Abe (2024-12-15 23:55 EST)




On 2024-12-12 11:08, Josh Luthman wrote:
I understand it is frustrating.  Analog phones can not be detected unless they're off hook so I don't see how a provider can detect between sitting idle or the cables cut.

How do you know for certain it is an outage in the area and not just the customer(s) you've talked to?

There is a requirement for outages required by the FCC.

On Thu, Dec 12, 2024 at 10:53 AM John Neiberger <jneiberger@gmail.com> wrote:
Understandable for a single customer. It sounds like this a huge part
of the town that has no phones, including the rural folks who live
outside of cell coverage, many of whom are elderly. I just found out
that they had indeed called CL to complain days ago and CL told them
they couldn't get out there to look at it until the 20th. These are
rural people with no backup to their landline who have been without
phone for days already and CL expects them to go another week or two?
Unbelievable. Also, when I called CL on their behalf, I was told they
had no record of an outage in the area.

Thankfully, I was able to reach someone at Lumen who was able to get
someone involved. There is supposed to be a tech there right now, but
he no-showed. I think an FCC complaint is in order.

On Thu, Dec 12, 2024 at 8:36 AM Josh Luthman
<josh@imaginenetworksllc.com> wrote:
>
> If it's landline copper phone, it's kind of hard for a provider to see the lack of customers off hook.  The electrical circuit being open is expected until the customer picks up the load/off hooks the phone.
>
> On Wed, Dec 11, 2024 at 11:54 PM John Neiberger <jneiberger@gmail.com> wrote:
>>
>> Yep. I finally found some contacts at Lumen who ran it up the chain. I
>> also did report it to the Colorado PUC. I'm still confused about how
>> so many homes and businesses could be without service and Centurylink
>> wouldn't know about it. It's a small town, and I'm starting to think
>> everyone thought that the phone company must know about it because
>> there so many affected, so no one bothered to call them. I don't know.
>> None of it makes any sense. But at least we have someone scheduled to
>> drive over there tomorrow and check it out.
>>
>> John
>>
>> On Wed, Dec 11, 2024 at 9:08 PM Evan Moyer <evmoy15@gmail.com> wrote:
>> >
>> > Have you tried filing a complaint with your state's public utility commission? POTS service is usually regulated by them.
>> >
>> > Just a thought
>> >
>> >
>> > On Wed, Dec 11, 2024, 7:52 PM John Neiberger <jneiberger@gmail.com> wrote:
>> >>
>> >> I apologize for using NANOG for this, but I need to get some traction
>> >> on a telephone outage affecting a large number of homes in a small
>> >> town that Centurylink seems to be unaware of. The affected customers
>> >> have had no phone service for days and none of them know what's going
>> >> on. Centurylink customer service says there are no outages in the area
>> >> and just want to dispatch a tech to an individual home rather than
>> >> escalate this as the emergency that it is. This is a rural area with
>> >> poor cell service, so many of these customers have no alternative. I'm
>> >> particularly concerned that many of the affected customers would be
>> >> unable to reach emergency services, and haven't been able to for 3-4
>> >> days already.
>> >>
>> >> If someone has a contact at Centurylink that can escalate this, please
>> >> contact me off-list.
>> >>
>> >> Many thanks!
>> >> John Neiberger



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