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Debugging Mystery File Descriptor Leaks

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16 min read | 4530 words | 0 views | 0 comments

A couple weeks ago, I discovered that one of my Asterisk servers was occasionally getting into a state where no new channels could be created, due to having used all available file descriptors (1024, which is a lot). It was pretty clear that we were looking at a file descriptor leak here.

Normally, this wouldn't be a hard issue to debug, as Asterisk comes with a DEBUG_FD_LEAKS compiler option that will let you see all open file descriptors, supposedly, by running core show fd from the CLI. This is to allow developers to easily debug possible file descriptor leaks.

Well, that didn't help much this time. The file descriptors in question didn't show up in the output of core show fd at all. However, if I checked /proc/PID/fd… — Read full post

What's the Deal with Call Waiting Deluxe?

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9 min read | 2600 words | 0 views | 0 comments

Call Waiting Deluxe — it's one of the coolest phone features you've probably never heard of or used. But seriously — what is it and how does it work?

Call Waiting is something many of us take for granted these days, but of course, it hasn't always been around. Nowadays, thanks to voicemail and call waiting, it's actually become rather rare to hear a busy signal on the public phone network, which is a mixed blessing in that it has become easier to evade people. A busy signal tells you a very specific thing: I'm busy right now, but call back in a little bit. If you hear a line go right to voicemail right away, it's not really clear what the deal is. Was that Call Forwarding Busy? Safe Call Forwarding? Probably not Call Forwarding Don't Answer. You can't even trust audibl… — Read full post

The End Is Near: FCC delivers final nail in the coffin to 7-digit dialing in 87 area codes

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14 min read | 4065 words | 0 views | 0 comments

UPDATE: The number of affected area codes is 87, not 88. As this continues to be an evolving situation, refer to the Anti-Digit Dialing League's official website for the latest details.

WASHINGTON, July 16, 2020—Today, the Federal Communications Commission adopted rules to establish 988 as the new, nationwide, 3-digit phone number for Americans in crisis to connect with suicide prevention and mental health crisis counselors. The rules require all phone service providers to direct all 988 calls to the existing National Suicide Prevention Lifeline by July 16, 2022.

To ensure that calls to 988 reach the National Suicide Prevention Lifeline, all covered providers will be required to implement 10-digit dia
… — Read full post

Discounted Teleconferencing Services for Impacted Businesses

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1 min read | 267 words | 0 views | 0 comments

At InterLinked, our daily operations have not been impacted by COVID-19 - however, we recognize that this is simply not true for the vast majority of people, businesses, and organizations.

Through our partnership with the Mountain Pacific Telephone Company, heavily discounted enterprise teleconferencing services are available to local businesses and non-profit organizations impacted by the current situation. For $5 a month, Mountain Pacific Telephone can provide a bridge with a dedicated dial-in number, unlimited attendees, no restrictions on conference length, and free recording and logging. PIN protection is optional and free. There are no extra fees, no hidden fees, and no hassles.

Due to the current economical situation, no payment is due for 30 days, and organizations… — Read full post

Smart911: A Dangerous and Distracting Delusion

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4 min read | 946 words | 0 views | 0 comments

It's well-known amongst dispatchers that, today, it's harder than ever for emergency responders to locate 911 callers.

This problem has tremendous implications for emergency callers. The consequences of using a mobile phone to call for help are so dire that there's now even an entire website purportedly dedicated to tackling this issue. Here's a description from the Smart911 website:

Today, 9-1-1 Can’t Find You

Over 80% of calls made to 9-1-1 come from mobile phones. When you dial 9-1-1 from a mobile phone, the 9-1-1 call takers have very little information to help you – only your phone number and a very general sense of your location.

This is a ser

… — Read full post

It Takes One

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7 min read | 1847 words | 0 views | 0 comments

On September 16, 2019, a bulletin was sent out to Panasonic customers, informing them that the venerable KX-TA824 PBX was going to be discontinued later that year. As of this writing, that time has already passed.

At first, I was surprised. The Panasonic KX-TA824 is truly a work of art. It's a compact, analog, partially electromechanical but mainly electronic Private Automatic Branch Exchange. With 3 trunks and 8 extensions out of the box, expandable to 24 lines, it's enough to get most people started on their never-ending journey of telephone collecting and telephone switching. Or (more boringly), serve as a home or small office phone system.

The KX-TA824 was my first PBX, and even at $99 used, it's a real bargain for what you get. It's much smaller than the 308 EASAPHONE… — Read full post

Californian Legislator promotes false solution to PG&E-induced outages

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8 min read | 2242 words | 0 views | 0 comments

Articles like this one are increasingly common, as PG&E service failures combined with consumer stupidity have made communications gaps painfully obvious to the masses.

However, it is angering and frustrating to see legislators promote false and dubious solutions to these issues, rather than addressing the underlying problems. California Senator Mike McGuire, whose constituency was heavily affected by the PG&E outages, is the latest to join in to the endless cascade of delusional and dangerous "solutions".

McGuire proposed a bill that would mandate cell towers in California's high-risk fire areas to have sufficient backup power for at least 2 days. Maybe … — Read full post

Experience the WOPR for Yourself — Relive WarGames as David Lightman

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2 min read | 412 words | 0 views | 0 comments

If you've ever clicked on the metadata at the top of each of my blog posts, among other things, you'll see a list of my favorite movies, and among them the 1983 movie WarGames. If everyone had a list like this, chances are you'd fine this title on a lot of them. It was extremely popular when it came out, and it continues to have a powerful hold on numerous people. References from the movie continue to permeate the fabric of society — both online and offline.

One of the most captivating parts of the 1983 film is the WOPR (War Operation Plan Response), an intelligent computer system that NORAD uses to help plan Cold War strategy, including determining how to best initiate or retaliate in nuclear war. David Lightman, the movie's protagonist, is a high school junior who skim… — Read full post

Running Your Own Phone Company

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2 min read | 388 words | 0 views | 0 comments

Have you ever thought of running your own telephone company?

If you're like most people, the answer is probably "no", without any question. But the idea used to be more romantic and enticing. Even during the era of Bell System dominance, from the late 1920s right through Divestiture in 1984, hundreds of independent phone companies existed and flourished — and many still do. Perhaps you remember the New City Telephone Company from the 1975 AT&T video production, "Run A Phone Company", in which high school students participated in a simulation of managing a phone company. While it was purely an educational initiative, it does prompt the … — Read full post

The growing irrelevance of toll-free numbers

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7 min read | 1870 words | 0 views | 0 comments

First, there were "ZEnith" exchanges, the original toll-free numbers. Since there was no Z on the dial, you would call the operator and she would connect you to a business on its dime, making the connection by looking up the number associated with a ZEnith number.

Finally, the Bell System launched Wide Area Telephone Service in 1961, which became used for the first direct-dial toll-free 1-800 numbers in 1966 and 1967. Originally toll-free exchanges were tied to geographic areas, much like area codes, but, gradually, like everything else in the phone network, things soon loosened up and, today, the modern toll-free network remains a fixture of television advertisements, magazine inserts, and radio jingles. What better way to entice the customer than offer to pay for his call?

… — Read full post

Landlines Win Again

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1 min read | 244 words | 0 views | 0 comments

Somewhere between 40% and 50% of households have a landline today, though the number of true traditional copper POTS lines is somewhere around 20%. (Think you have a "true" landline? You might be in for a nasty surprise.)

Yet, at least in theory, most people have a lot more love for the humble landline than they let on. According to a 2014 Pew Research Poll, "the public felt most secure using landline phones": The public feels most secure using landline phones, least secure on social media

Personally, this is n… — Read full post

The Truth About Fiber-Optics

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23 min read | 6647 words | 0 views | 0 comments

Fiber-optic cables aren't exactly new. Part of the reason for the 2001 recession was a tech crash caused by excessive buildout of fiber, most of which remained "dark" for years. Fiber has been used for Internet backbones as well as long-distance trunks in the PSTN, but only recently has the idea of extending fiber directly to the home become pervasive. I won't give an overview of fiber here, so for some history and details about how fiber-optic communications works, you can check out Broadband Now.

Until recently, I'd been fairly ambivalent about fiber-optics. Fiber is much faster than cable or DSL Internet, but it's much more expensive. The cost of fiber-optic cable and connectors is exorbitant: which is why computers … — Read full post

Why Splits Are Preferable To Overlays

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16 min read | 4502 words | 0 views | 0 comments

How many digits constitute a telephone number?

The most common answers, at least in the United States, which is part of the North American Numbering Plan (NANP), are 7 and 10. There's a pretty good chance that whatever answer YOU gave says something about your age.

For the record, telephone numbers are 7 digits long. They have been since 1947 when AT&T devised the NANP, in which area codes, officially called Numbering Plan Areas (NPAs) played a prominent role. It's why you write area codes in parentheses (unless you don't know how to write telephone numbers correctly). The NANP unified the Bell System in an era when there were no real standards for telephone numbers. Some communities dialed 6 digits, others dialed 5 — still smaller communities dialed 4 digits.… — Read full post

Adopt A Payphone

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4 min read | 916 words | 0 views | 0 comments

Adopt A Highway began as a local effort in Texas in the 1980s. Today, the program has spread all over the United States. It's hard to drive almost anywhere these days without seeing the iconic "Adopt A Highway" signs on the edge of the road. That's all great, and the idea could prove to have other useful applications as well.

Today, most payphones are owned by payphone providers, not telephone companies. Most telephone companies got out of the payphone business in the late 1990s or early 2000s. Today, PTS (Pacific Telemanagement Services) is the largest payphone provider in the U.S. If you've used a payphone recently, chances are good that it's a PTS phone. They have phones on both coasts and everywhere inbetween. Since they're not owned by the telephone company, they obviously d… — Read full post

The Telephone Songs

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2 min read | 496 words | 0 views | 0 comments

Depending on how old you are, you may remember watching a video called "Telezonia" when you were in grade school, instructing young children how to use the telephone in a musical and playful way.

If you do, hats off to you! If not, that just means you're probably young.

The most famous Bell System instructional video was called "Adventures in Telezonia". There were multiple videos made over the years with this name, but the most popular one was released in the 1970s. The plot? According to AT&T Archives, which releases Bell System videos, "It starts off like a typical short film cautionary tale, but once they take a trip inside the telephone, things go terribly weird. This film is a cult classic."

The music has become a classic in and of itself, too. Below are a… — Read full post

The term "cell phone" is a misnomer

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5 min read | 1301 words | 0 views | 0 comments

“Phone” used to be just short for telephone. Telephones were phones and phones were telephones. Today, that is not the case. "Telephone" adheres to the denotation of the word, whereas the connotation of "phone" has changed. Think about it: the word “telephone” is generally only used to refer to corded fixed-line phones. Today, all telephones are still phones, but not all phones are telephones. Mobile phones and cordless phones are generally never referred to as “telephones”.

In fact, a dictionary definition of telephone says it is “a system that converts acoustic vibrations to electrical signals in order to transmit sound.” Neither cell phones or Voice-over-Internet-Protocol phones fit this definition. Only standard analog landline phones fit this definition, alth… — Read full post

Monopoly Isn't Always A Bad Thing

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9 min read | 2638 words | 0 views | 0 comments

Monopoly isn't necessarily bad. In fact, sometimes it can be a good thing. A very good thing!

Most economics classes foster a passionate dislike of monopolies in students. But this dislike is not necessarily deserved. Economics classes teach us about seemingly malevolent monopolies that wreacked havoc on the economy. But most economics courses omit discussion of the largest monopoly ever to have existed — perhaps the most benevolent monopoly of all: the Bell System.

That's right, Ma Bell the monopoly! Technically, the Bell System — headed by American Bell Telephone until 1899 and American Telephone and Telegraph Company (AT&T) from 1899 until 1984 — was not a complete monopoly in the United States and Canada, although it was a geographic monopoly where it… — Read full post

A Professional Perspective: Kari’s Law

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8 min read | 2303 words | 0 views | 0 comments

On December 1, 2013, Kari Rene Hunt was murdered by her estranged husband whom she was intending to divorce. She agreed to meet him at a local motel to leave their children with him for a short visitation while he was in town. Her estranged husband ambushed her in the motel room and cornered her in the restroom. During the struggle and resulting death of Kari, her oldest daughter, age 9, (name withheld for privacy) attempted to dial 911 from the motel room phone. She followed instructions as taught by her mother on the way to call for help but she was never instructed that in some hotels and motels you must first dial a “9” and then 911.

This is the beginning of … — Read full post

What The Color Coded Tape Means On Store Columns

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  activism critique ethics health

1 min read | 222 words | 539 views | 0 comments

Many stores like Walmart and Sam's Club, especially the older ones, color-code their poles. Have you ever noticed colored pieces of tape at the top of some of these poles? Yes, they actually mean something!

  • Blue — Blue tape at the top of the pole indicates that there is a telephone at the bottom of the pole.
  • Yellow — Yellow indicates a spill clean-up station is located at the bottom of the pole.
  • Red — Red indicates that a fire extinguisher is located at the bottom of the pole. Hopefully, you'll never need to look for this one.

Some poles may have more than one piece of tape. For example, a pole may claim a blue piece of tape and a yellow piece of tape. That means both a telephone and a spill clean-up… — Read full post

A Cool "Telephone Trick" That Will Impress Your Friends

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1 min read | 77 words | 470 views | 0 comments

  1. First, pick any 7-digit telephone number. For example — 567-1234
  2. Now, punch in the first 3 digits of the number you chose
  3. Multiply the number by 80
  4. Add 1 to the result
  5. Now, multiply that answer by 250
  6. Now, add the last four digits of your telephone number to the result from Step 5
  7. Add the last four digits of your telephone number again
  8. Subtract 250 from your result
  9. Now, divide the number by 2
  10. You should now end up with the number you chose

A Couple Videos Guaranteed to Get You Laughing…

Posted by Contributor

  environment health policy

1 min read | 132 words | 449 views | 0 comments

Someone once said that laughter is the best medicine. Even if you're not sick right now — I'm sure we could all use a little laugh right now. Well, I wanted to take a minute and share out some videos I've seen in the past that are guaranteed to get you laughing. If they don't well, let me know and we'll chat. This first video addresses the notion that desktop computers are stationary and stay in one place — all the time. Well, in this video, some students have decided to attend a lecture and they bring their desktops with them, computers, keyboards, monitors, dial-up modems, and all. In this second video, you'll witness what happens when… — Read full post

Yes, you still need a landline!

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11 min read | 3112 words | 583 views | 0 comments

Don't even think about giving up your landline! Yes, you still need it — same goes for your desktop. This concept is one I've been preaching for a long time now, but recently this past Tuesday an event occurred that made me want to reiterate my point. Recently at our school, we experienced a power outage. In our area of the state, power outages are not uncommon, but they are not a frequent occurrence. This particular day we experienced some mild gusts, but nothing to warrant any severe weather precautions. Regardless, with about half an hour left until the end of the school day, the power went out; at that moment I was on stage with one of the bands prepping for a concert later that night — the overhead lights went out and then flickered back on. They flicked off and on again a coup… — Read full post