Path: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail
From: Don Y <blockedofcourse@foo.invalid>
Newsgroups: sci.electronics.design
Subject: Re: iPhone battery replacement
Date: Sat, 8 Jun 2024 14:42:34 -0700
Organization: A noiseless patient Spider
Lines: 60
Message-ID: <v42j9e$2r5nm$1@dont-email.me>
References: <v3g1us$2v8q0$1@dont-email.me>
 <i14n5jlsbj35q8distkm79dqkuuhn5fvp1@4ax.com> <v3g55i$2vrtg$2@dont-email.me>
 <fo6n5jp6mjr31oloi8vm4mmuqj9jk68lp9@4ax.com> <v3g96k$30jrf$1@dont-email.me>
 <OW98O.50235$5bN4.21114@fx17.iad> <v3saei$1glle$1@dont-email.me>
 <bY%8O.209$U5Ua.127@fx36.iad> <v42862$2noho$1@dont-email.me>
 <mB39O.30567$2JEf.30311@fx14.iad>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit
Injection-Date: Sat, 08 Jun 2024 23:43:12 +0200 (CEST)
Injection-Info: dont-email.me; posting-host="06ad93f0b9851620f6d01b846ed5bed9";
	logging-data="2987766"; mail-complaints-to="abuse@eternal-september.org";	posting-account="U2FsdGVkX18asDesJJtrUIDAyepiyHYo"
User-Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:102.0) Gecko/20100101
 Thunderbird/102.2.2
Cancel-Lock: sha1:63FoMuU3eGN2e/FXLFnSPFYu6jg=
In-Reply-To: <mB39O.30567$2JEf.30311@fx14.iad>
Content-Language: en-US
Bytes: 4487

On 6/8/2024 1:57 PM, Bertrand Sindri wrote:
>> I.e., whatever criteria are used, it obviously is designed to reject
>> MOST sources of line noise.  Pity the folks trapped in that burning
>> building who fail to hit whatever design window is accepted (WHILE
>> the copper is burning)
> 
> Which is just what the atty., worried about a possible lawsuit, is
> worried about, and why they force the engineers to program the switch
> to recognize "stuff" that isn't perfectly to spec.

Remember, here, this is all covered by law that clearly defines the
responsibilities of the provider.  One could see the telco's lawyer arguing:
"And, should we also detect two hookflashes, followed by a 3 minute delay and
another four hookflashes, a 2 second delay and three more in rapid succession
as the leading '9' -- and, not an elderly person slowly dialing 2 4 3..."

Recognizing "outliers" isn't easy.  I suspect the switch doesn't even look
for a '9' followed by a '1' and another '1'.  Rather, some "abnormal"
line activity.  Could a two-year-old playing with a phone happen to dial
an emergency services number -- how is 6 2 1 1 1 not seen as 9 1 1?

The switch likely can't store much state for each possible subscriber.
So, it can't "learn" what to expect from a particular line:  "Oh,
that's Don's line and the insulation on his pair have obviously degraded
to result in lots of noise on an otherwise functioning pair."

Instead, it has to adopt a one-size-fits-all algorithm.  But, this has to
address legitimate 911 (dial pulsed) calls accepting the tolerances on
how fast the dial can "return to home" (in the presence of a "fat finger")
as well as all of these hypothesized attempts at POSSIBLY needing assistance
and being inept in your dialing.

<https://maker.pro/forums/threads/can-telephone-noise-dial-911.66494/>
<https://support.google.com/googlepixelwatch/thread/205920957/911-call-while-i-was-sleeping?hl=en>
<https://www.nytimes.com/2023/02/03/health/apple-watch-911-emergency-call.html>

The downside of false positives is that of increased externalities; someone
ELSE pays for the problem (potentially, adding bias to future emergency
responses -- "boy who cried wolf").

     "In Grand County, home to a busy mountain called Winter Park, Sheriff
     Brett Schroetlin decided in late December to devote less attention to
     the crash-detection calls. Now if a 911 operator receives one from the
     slopes and no one is on the other end of the line, they know to ignore
     the call; no more referrals or follow-ups. None of the ghost calls so
     far have been real emergencies, Sheriff Schroetlin reasoned, and he
     couldn’t afford to waste limited resources."

I put a weight on each "potential emergency" scenario that I detect.
I will bother the occupant before I will bother a (remote) family
member.  The family member before a nearby neighbor.  And, the neighbor
before the police.

But, I can do this because I have more information than a string of break/makes
as well as intimate knowledge of the occupant and scene.