>>> 2021-02-28 manzano base part 1

First, a technical note: I had noticed in my web server logs a few times that I receive a weird number of requests for individual posts that are malformed with regards to the spaces. Either the spaces are stripped or, more commonly, are "double escaped" with the %20 escape transformed into %2520. I meant to dig into this but quite frankly forgot, until reader Rick emailed me that Twitter seems to do this when you copy and paste a URL. So I made a change today so that the "permalink" file names now have hyphens instead of spaces.

By no effort of my own, but rather because my Enterprise Content Mismanagement System just dumps files and forgets about them, the old links will continue to work as well. Tweet away, if that's a thing you do. For extra fun, try to find the posts where I put "2020" instead of "2021" in the title, and then noticed when I generated the website, and then fixed it, but the old file is still there. I call them mystery posts. They're just like the normal ones but with somehow even more mistakes.

To the point: I have posted another video over on YouTube. It's the first part of a two-part series where I talk about the history of Manzano Base and then review some environmental contamination and remediation sites within it. For flavor, Manzano Base is one of the first two National Stockpile Sites for storage and maintenance of nuclear weapons and is one of the few times that rumours of a secret government base dug into a mountain turned out to be generally correct.

I also improved my microphone situation and it clips far less often. Now I just need to cover my walls in foam. Over the tin foil, of course.

• YouTube: https://youtu.be/BMWPDLqzTy4
• Peertube: https://toobnix.org/videos/watch/f1962dcc-4700-4fd6-8fcc-500e860a9d43

>>> 2021-02-27 kitchen videos

It's important to take a break every once in a while, so let's distract ourselves from telephony for a bit and talk about another old favorite of mine, point of sale. The needs of the point of sale have produced a number of interesting computer systems, but restaurants have a particular set of constraints and requirements that have produced a universe of computer solutions dedicated to restaurants.

Unlike retail point of sale, which does seem to have a small corps of amateur historians, it's relatively difficult to find information on the history of restaurant systems. As a result, some of what I say here will be a bit speculative, based on assumptions made from things that I do know. But to start, what differentiates restaurant POS from other POS applications?

We previously discussed how POS equipment has evolved over years from mechanical cash registers that were limited to totaling purchase amounts to enterprise computer systems that automate back-office functions like inventory management and reporting. Similarly, restaurant POS systems have expanded over time to cover automation needs specifically to restaurants. A full-featured restaurant POS is expected to coordinate the kitchen with the front of house (FOH) while also automating the more bureaucratic parts of the FOH like assigning parties to tables, reserving tables, tip accounting, etc.

Restaurants vary widely in how much they lean on automation for these functions. Generally, larger and more "corporate" restaurants (e.g. chains), and especially quick-service and fast-food restaurants, are likely to lean more heavily on automation than more local, boutique operations. As you might imagine from that generalization, McDonalds is more or less the peak of conventional restaurant technology; given the history of that chain it might not be surprising that it was also an important innovator in the field.

It is widely reported that the first restaurant POS system was created in 1974 by Brobeck and Associates and was used by McDonalds. This is, of course, wrong. Not completely wrong, but wrong in a way that makes research rather frustrating. William Brobeck was a nuclear physicist by training, and through his companies Brobeck and Associates and Cyclotron Corp is best known for his work designing cyclotrons for various applications. He was also, I have found, a consummate tinkerer, and published designs and filed patents for various robotic devices. As best I can tell, Brobeck and Associates never had anything to do with any POS systems, but Brobeck also founded a company called Transactron to do exactly that.

In fact, once you know what to search for, you'll find that the Computer History Museum has a Transactron McDonalds POS device in their collection. I have found photos of the same device branded Transactron, and CHM lists it as manufactured by Transactron, but theirs actually bears the logo of "Courier Terminal Systems." There is very little information out there about Courier[1]. The patent covering the device is in the name of Transactron, but I speculate that at least early on Transactron may have partnered with Courier to actually manufacture the unit. Oddly, the Computer History Museum also lists their example as "circa 1972," which seems unlikely considering that the patent was filed 1974 and most other sources say that McDonalds began use of the system that year. But, well, they said "circa" after all.

The Transactron system is well described by the patent, and is surprisingly feature-rich for the time. Based around an Intel 8008, it consists of multiple terminals with a grid of buttons, most of which are labeled with menu items but some of which contain numeric keys or function keys (such as total). Orders can be edited as they are entered and can be stored for recall, both of which were features that surprised me for such an early example.

The terminals seem to have been "dumb" devices and the microcomputer logic was housed in a central location and connected to a printer. Each order entered at a terminal would be printed.

One thing I am very curious about is the extent of the relationship between Transactron and McDonalds. Was the system originally designed as a partnership, or did McDonalds purchase it more or less off the shelf? If it was originally designed as a partnership or on commission, that might explain why it is widely said that Brobeck and Associates designed the device while the patent is under the name of Transactron---perhaps they formed Transactron as a company to market the device, after Brobeck and Associates designed it. Oddly, online biographies of Brobeck tend to completely omit his involvement in something as impressive as the first automation of McDonalds, apparently obscure compared to his work on cyclotrons. It seems to be, overall, rather forgotten.

This basic design of a restaurant POS has proven quite durable and is still in use today in many smaller or less automated restaurants. Orders are entered front of house and, once committed, are printed in the form of a "kitchen ticket" by a printer in the kitchen. This is essentially just a light automation of the older practice of waiters hand-writing orders on a paper ticket which they deliver to the kitchen, which is once again still in use at many restaurants today.

The kitchen printer is a somewhat specialized animal. The direct thermal paper typically used for POS applications (e.g. for receipts) does not hold up well to exposure to grease and heat, both of which are present in abundance in the kitchen. For that reason, kitchen printers are typically actually impact printers on plain paper, and the most popular model from Epson makes use of a two-part tape that allows for printing in black or red---a relatively inexpensive enhancement for impact printers that can't be done with direct thermal printers. This leads to a sort of irony that kitchen tickets are often printed in two colors (e.g. red for substitutions), which is a bit fancier than the consumer-facing receipts. On the other hand, most major restaurants seem to be using a twenty-year-old printer with a dry tape and in poor adjustment that produces extremely light output. Printers always have their problems [2].

You can likely see an obvious enhancement to this concept of the FOH POS automatically 'sending' the ticket to the kitchen via a kitchen printer. What if, instead of a printed slip of paper, the kitchen made use of computers to view and manage orders as well? This is clearly an interesting idea, but the practical constraints of operating computers in the harsh kitchen environment made it impractical for many years.

As best I can tell, the first such system was patented in 1981. The term was not yet in use, but by the end of the '90s such a system would be called a "Kitchen Display System" or KDS (less frequently Kitchen Video System or KVS). This early patent described a system where a series of letters were displayed on a CRT corresponding to different items which had been ordered. It is clearly very primitive, but was presumably heavily limited by the microcomputer technology of the time.

This patent was originally assigned to OCR Marketing Associates, which I can find no information about. However, in 1988 it was assigned to the Stanley Hayman company, and one of the inventors, Richard Hayman, is listed on later Hayman company patents and just by the name may have been related to the founder [3]. As a result, I suspect OCR Marketing Associates may have been a subsidiary or was otherwise related to the Hayman company from the beginning.

In any case, much like Brobeck's 1974 work, Hayman et al's 1981 patent lays out the groundwork for the kitchen display systems that are still in use today. Busy restaurant kitchens often consist of multiple people at various stations which specialize in specific items or methods of preparation. As a result, a single order is often cooked by multiple people, and finally an individual called an expediter will collect the items to consolidate them into one dish. This basic process can be seen very clearly at most fast food restaurants, where line cooks arranged in an assembly-line fashion will slide sandwiches down a counter while a fry cook collects fried items and puts them on a tray; the expediter gathers both and bags them to finish a typical burger-and-fries combo.

This process can clearly be frustrated by the need to pass a paper ticket around, but multiple paper tickets create their own problems as it becomes difficult for the expediter to be sure what goes together. Instead, the Hayman patent describes a system in which each workstation has a computer display which shows only the items to be done at that station. The expediter's display does not show an order at all until the cooks have indicated that they completed the preparation of the items in the order, so they should be ready for the expediter to collect.

Actually the Hayman system is not quite that sophisticated, it simplifies the electronics by having many of the displays be exact mirrors with symbols indicating which station should pay attention to which items. The expediter, though, is provided with an individually controlled display so that they are not distracted or confused by the items not yet ready for them.

In the Hayman patent, a standard keyboard is apparently used for data entry in the kitchen. In the kitchen environment this must have been a rather high-maintenance piece of hardware. In part due to the greasy environment in a kitchen and in part because of the relatively higher complexity of connecting multiple keyboards to a single computer, the keyboard would be replaced in KDS applications by a "bump bar."

A bump bar is an input device, usually using membrane keys for ease of cleaning, that usually consists of a row of numbers corresponding to positions on the display where order tickets are shown, and several action buttons, the most important of which is "bump." Selecting a ticket and pressing "bump" indicates that the ticket is complete at that station. Typically, once all stations preparing components of an order bump the ticket, the ticket will appear at the expediting station.

An important parallel innovation in point of sale was the increasing popularity of the microcomputer. Most point of sale systems into the '90s were based on a mainframe architecture in which individual devices (cash registers, kitchen display stations, etc) acted as terminals to a midcomputer or minicomputer. By the '80s, though, it became possible (albeit complex) to use a system of networked microcomputers to build a similar system.

The relation of the microcomputer to to restaurant POS is rather interesting due to an interesting central character, Gene Mosher. Mosher operated delis in New York City and was apparently also a bit of a dweeb. He reports that, in 1978, he started writing software for his early-production Apple II to manage POS at his delis. In 1986, he upgraded to an Atari ST with a touchscreen. He marketed his touchscreen restaurant POS system (believed to be the first) under the name ViewTouch, and delightfully, a descendant of ViewTouch is open-source today, still maintained by Mosher and now targeting devices like tablets and the Raspberry Pi.

In fact, the development of practical touchscreens was nearly as significant to POS technology as networked microcomputers. Virtually all restaurant POS today is touchscreen at the FOH, and increasingly many retail systems are as well. Mosher's influence on touchscreen POS is clear. The faux marble GIF background is decidedly dated, but otherwise ViewTouch looks nearly identical to most touchscreen restaurant POS products today. Mosher seems justifiably a bit peeved at the extent to which major players like NCR seem to have copied his work.

That brings us more or less to the modern day of traditional, enterprise restaurant POS solutions. For large companies, there are two dominant players: Oracle Micros, and NCR Aloha. Micros, today part of Larry Ellison's wrathful empire, actually acquired the previously mentioned Hayman company in 1999 but seems to have licensed patents from them even earlier, as Micros was an early player in the KDS market with a terminal-and-minicomputer solution. By the time of the acquisition, Hayman was actually described primarily as a value-added reseller (VAR) of Micros, suggesting that they had lost their technology edge. The acquisition of Hayman was part of a larger trend (still going on today) of legacy technology vendors shifting towards direct-to-consumer sales by acquiring their former distributors and VARs.

Aloha was established to market the (believed) first Windows-based restaurant POS system in 1992, and so is firmly rooted in networked microcomputer solutions. They were later acquired by Radiant Systems, and you will occasionally still see Aloha systems showing the Radiant logo. More recently, though, Radiant was acquired by POS giant NCR, leaving the current branding.

Despite the separate histories of Micros and Aloha, both are, today, microcomputer-based. Aloha remains Windows hosted, while Micros is available for both Windows and Oracle Linux (it was presumably UNIX based for a time). Micros is often (but not necessarily) run directly on Oracle-manufactured hardware, but Aloha is most commonly seen on purpose-built restaurant POS devices from Elo Touchsystems. The two are physically fairly similar, and if you will picture with me, in your mind's eye, the device that a waiter taps on, you are seeing either a Micros Workstation or an Elo Touchsystems product.

Because of the difficult kitchen environment, touchscreens are not common for KDS. Most modern KDS still use a physical bump bar, which are available from some vendors with lightning connectors, because everything has to be these days.

In the modern world most of these established restaurant solutions are starting to look pretty legacy, due to competition from several dozen upstarts with a basic knowledge of PHP and a love of iPads. A quick google for "restaurant pos" will find you a dozen iOS-based, cloud-backed restaurant POS solutions with varying degrees of feature-completeness compared to legacy solutions.

Because of the relatively high cost of kitchen-quality hardware, and hardware in general [4], it's common for these solutions to still use a traditional kitchen printer or lack kitchen integration at all. Similarly, the credit card situation might be fiddly and dependent on Bluetooth and battery charging, and all of the other limitations I have previously discussed as coming from the increasing commodification of computing.

Or, for new readers, I will attempt to quickly summarize this theory of mine in the context of what we have just discussed: The restaurant POS solutions of the '80s, '90s, and even '00s were designed nearly full-stack by dedicated engineers for a specific purpose. As a result, they are very well suited for that purpose, but they are also expensive and often only available though irritating sets of VARs and service contracts due to the long shadow of IBM's strategy of computers as leased rather than owned. "Modern" restaurant POS solutions are rapidly designed on top of consumer hardware and consumer operating systems, which makes them less expensive and (at least perceptually) more friendly, but at the same time, tends to make them less suited for purpose.

In this way, the evolution of computing as a universal commodity has made computer systems more widely available but also subtly and pervasively worse.

Consider an example: touchscreens are specifically uncommon in the kitchen for legacy systems because kitchen staff often have dirty hands and/or are wearing gloves. These problems can be ameliorated by either using a physical bump bar (most common due to low cost, ease of cleaning, etc), or by the use of resistive or acoustic touchscreens. For similar reasons, dedicated touchscreen POS devices typically use resistive or acoustic touchscreens because FOH staff as well sometimes wear gloves, and are also fond of doing things like using the edge of a credit card to tap buttons.

iPads, though, are the development platform of today, and are not available with bump bars or non-capacitive touchscreens. Although in some cases specialized hardware features are available as accessories, the majority of users of such "off-the-shelf" hardware systems are attracted to them as low-cost, all-in-one solutions, and so instead of purchasing specialized accessories they just settle for the limitations presented by a consumer tablet in a special-purpose commercial application. Consider, for example, how rare it is for Square-based stores to be able to produce a printed receipt, something that was long considered an absolutely core feature of a POS device.

For relatively high-cost specialized systems, integration is usually viewed as a core part of the offering. For this reason, POS solutions, KDS, hospitality systems, etc produced by different major vendors can typically be integrated with each other. Producers of modern off-the-shelf systems tend to view integration as an unnecessary expense, though, which leads to the comical situation of restaurants with four or more iPads (someone who had heard this rant from me once sent me a photo of a restaurant with six), each of which runs one app, several usually being for different delivery services. Someone at the front desk has to copy incoming delivery orders from one iPad to another, the paragon of computing efficiency.

None of these problems are necessary an intrinsic limitation of the modern tech industry but they do seem to be, to at least some large degree, an intrinsic result of the values and motivations of tech entrepreneurs and investors, which usually value time-to-market over fitness-for-purpose.

You see, the development of the modern restaurant POS has taken the better part of fifty years. A minimum viable version of a restaurant POS can be produced in a week, and someone will probably give you $25mm to sell it to small restaurants at a cost too low to refuse. iPad not included.

I have left out several parts of this theory such as the powerful component of consumer-as-employee expectations, and left out the entire part of this story which is Oracle repeatedly and aggressively scaring off customers, but I've already put a lot of words here. Continuing this line of inquiry, though, in the future I will be talking about hospitality management systems: POS for hotels.

[1] The CHM also has an old Courier brochure listing a Phoenix address and advertising a terminal they apparently manufactured, so they seem to have been a small company with an in-house manufacturing capability.

[2] That's not entirely true, the Epson TM series direct thermal printers are flawless and I love them, which is why I keep buying used ones and finding stupid uses for them around my house. I think I've mentioned this before but, like, it's basically my main hobby.

[3] I found an obituary that would seem to confirm that Richard Hayman was Stanley Hayman's son, but I'm not entirely sure it's the right Haymans.

[4] Yes, "they can't afford hardware" is a weird thing to say about businesses that view the iPad as an embedded platform, but somehow it seems like in the mind of many small businesses the Apple store hits the wallet a lot softer than the same bill from a POS vendor.

>>> 2021-02-20 555 500 710 etc

We are probably all familiar with "555" telephone numbers. The basic idea is that the 555 exchange code (or NXX in a NANP NXX-XXXX number) is reserved for use in fiction. Of course, this isn't actually true at all, but that hasn't stopped basically every work of fiction putting their imaginary telephone numbers in the 555 exchange.

In reality, the 555 exchange has a somewhat bumpy history, as is the case with most "special purpose" telephone ranges. Seemingly from the genesis of NANP as a formal numbering standard, the 555 exchange was reserved for special use by telcos, and was not to be used for normal subscriber lines. The 555 exchange accumulated various and sundry uses, but most prominently, starting in the early '60s it was used for directory service at 555-1212 in nearly all NPAs (area codes). This was nearly the only successful use of the 555 exchange, leaving it mostly empty.

Because the 555 exchange was conveniently largely out of use, it became common for the entertainment industry to use 555 numbers in fiction. Wikipedia makes the claim that the telephone industry had specifically recommended 555 numbers for this use in the '60s, and while this is rather thinly sourced, it's not hard to believe as any odd person in a technical role at a telephone company might have suggested 555 as an exchange with extremely few assigned numbers.

In any case, the use of 555 numbers for fiction was somewhat informal. This changed in 1994, when the telephone industry regretted leaving an entire exchange out of use and formed a working group which allowed 555 numbers to be assigned to nationwide communications services. The idea was that 555 numbers would have the unusual property of working nationwide when dialed as only seven digits, somewhat like an early version of SMS short codes.

Because the use of 555 numbers in fiction was longstanding, the working group explicitly reserved numbers starting 555-01 for use in fiction. This, in 1994, is when this practice became formalized---but only for those 100 numbers.

In practice the 555 service as imagined was unsuccessful, and in the 2010s the use was eliminated more or less by handshake agreement. Much like the pre-1994 state, the only valid phone numbers in the 555 exchange are 555-1212 for directory assistance, and 555-4334. This latter number is apparently still assigned for a nationwide use but no one specifies what use.

I did a bit of digging, and... came up empty. 555-4334 in a number of area codes turns up nothing from the CNAM service I use. Similar attempts with a couple of validation/carrier lookup vendors returned different types of useless results. I haven't found any mention of the number in old newspapers, with the interesting exception of some newspapers listing their classified ads with exclusively 555 numbers, including 4334.

It was not an unusual practice at the time for newspapers to provide special "voice mail box" numbers for classified ads, but to my knowledge the use of 555 was not typical. The first newspapers to do so were almost all in Utah, which hints that it may have originated as a choice by a local telco, potentially Mountain Bell but maybe more likely an independent. I will do some more digging into this over time. It's interesting in that it suggests a major use of 555 numbers which no document I've seen on the history of the exchange mentions. This practice doesn't seem to have been eliminated until the 1994 reallocation.

I also learned that in 2009 you could get a rebate of $7,555 or $4,334 on a new Dodge Nitro. Isn't OCR fun?

Finally, I located an older FCC report (dated 1997) that lists 555-4334 as allocated to MCI mail, an early e-mail service. MCI mail access was initially by modem, and so it's possible that 555-4334 was used as an access number, although an 800 number was also provided for this purpose and 4334 is not mentioned anywhere I can find as an access number. An interesting feature of MCI Mail was its ability to forwarded email to postal addresses (by printing and mailing it) or by fax or teletype, so I speculate that 555-4334 may have been used as a return number for TTY messages, since the TTY integration was apparently bidirectional. In any case, another document noted that 555-4334 was permitted to remain in service until that service ended, which may have been an allowance due to the fact that MCI was a telephone carrier (and thus had greater sway over the working group) and that replacing the number may have been technically difficult.

Today, it remains the case that only 555-01xx is properly allocated for fictional use. However, the 555 exchange as a whole is as dead (or considering the use by newspapers, much more dead) than ever before, so it remains common to use the entire 555 exchange in fiction.

Oddly, the 555 NPA (rather than exchange) is allocated for similar applications, but as far as I can tell it is not in use.

The failure of the post-1994 use of 555 for a "short dialing service" reflects a larger series of telco failures that has left some other special prefixes. In the '90s, a great deal of attention was directed towards "non-geographic" dialing. Because the telephone system connected the nation together, why not have a method of telephone dialing which is independent of geography? Well, as it turns out, there are several reasons, but this didn't stop anyone from trying.

Although there were a hodgepodge of other attempts, the first major non-geographic dialing scheme is contained in the special 700 NPA (area code). This NPA was allocated as a direct result of the breakup of the Bell system for use directly by interexchange (long-distance) carriers, since all existing numbering ranges were allocated to the exchange (local) carriers. The primary service offered in this range was "EasyReach 700" from AT&T, which was basically carrier-managed "follow-me."

Follow-me is a common feature of business telephone systems that allows a call to a given number (extension or DID) to be directed to one or more real extensions depending on the location of the intended recipient. For example, a call to a professional might go to their desk or to an assistant depending on whether they are in the office, while an auto mechanic might have a call to a general contact number ring at the front desk or in the shop depending on where they are.

EasyReach 700 moved this same concept from the PABX to the telephone network, making it possible for follow-me to span the nation and making it accessible to businesses without an (expensive) PABX. For example, a consumer with two different homes could get a 700 number and set it to forward to whichever house they were staying in, while a traveling salesman could set their 700 number to forward to whichever hotel they were staying in.

EasyReach was a failure. There were several reasons, but the most significant relates to the billing climate of the time. Today, unlimited long-distance is so ubiquitous that the issue may not be obvious, or you might naively assume that AT&T had found a way to resolve the long distance cost issue. They did not---in fact, they came up with something worse. The owner of a 700 number could set it up to either bill forward (to the caller) or reverse (to the callee). This meant that the caller of a 700 number had virtually no way to determine whether the call would be free or charged at long-distance rate, and this was a huge deterrent to use of these numbers.

Today, this and other uses of the 700 NPA have all died out, leaving 700 a nearly empty NPA. Like other empty NPAs, 700 is sometimes hijacked for special uses by non-mainstream carriers and corporate phone systems. If my hazy memory is correct, the 700 NPA was used by GE's interoffice leased-line long distance network when I briefly worked for a GE business. Wikipedia says that WalMart still uses it this way.

Since the 700 NPA was such a success, AT&T naturally decided to do it again. In 1993, NANP allocated the 500 NPA to Personal Communications Service (PCS), not to be confused with Personal Communications Service (PCS). In fact, the same term was allocated to two completely different purposes by two different telecom organizations within a few years. The latter refers to a set of services offered by a wireless network, e.g. Sprint PCS, while the former refers to... EasyReach 700 all over again, except for now it's called True Connections.

True Connections failed for the exact same reasons as EasyReach 700, and was officially eliminated in 2000, but by this point AT&T had already largely replaced it with a service using 800 numbers which were of course always reverse billed... which you and I might think is obviously what they should have done in the first place, but back in the '90s toll-free and non-geographic were viewed as being different animals. It seems to have taken AT&T a long time to catch on to the fact that the realities of long-distance billing required that they be closely linked.

The concept of PCS (the non-geographic dialing one) did not die out with True Connections, and additional NPAs were allocated to the same purpose, generally in the format of 5 followed by the same digit twice, much like 800. 500 numbers continue to be non-geographic and the billing situation remains odd, but that hasn't stopped the use of 500 for certain uses like modem banks for ISPs and some calling cards. Very few 500 numbers remain in use today despite the multiple allocated 500 codes, and due to the billing issues it's common for outbound calls to 500 numbers to be blocked. Similar to 700, it's not unusual for 500 to be used for internal purposes, although this is probably less of a good idea since PCS services in the 500 NPA have not officially been ended.

500 and related PCS area codes (500 has a surprising number of overlays considering how obscure its usage is) also see use for other miscellaneous telco applications. For example, the 588 area code, also assigned to PCS, was (and may still be) used by Verizon Wireless to generate temporary phone numbers used to bridge their proprietary enhanced SMS service to other carriers.

The 500 NPA is sometimes referred to today as a "machine to machine" service, since it's now largely used for modems. Another set of NPAs reserved for machine-to-machine uses were a set ending in 10 - 510, 610, 710, 810, 910. These were used for an AT&T-run (later Western Union) teletext service, in which these numbers were used for higher-quality local circuits with TTYs attached. The service was successful in its era, but after the advent of the fax machine fell out of use.

In 1983, the now-unused 710 NPA was reallocated to the US Federal Government, making it de facto a non-geographic NPA. While the 710 area code had once been envisioned as a unifying NPA for federal offices throughout the country (this made a great deal of sense since most federal offices had their telephone service on special contract terms with AT&T that allowed for free calling between them), but this never seems to have caught on. As far as I can tell, for the entire history of 710's assignment to the federal government it has only contained one valid number, 710-627-4387, which is the access number for the Government Emergency Telephone Service (GETS). Telephone call prioritization schemes like this may be a topic I cover in the future. 710's "waste of space" has attracted some criticism[1].

The 600 area code, following a pattern, is also allocated for non-geographic use but in Canada, and has some overlay codes (611, 622, etc) as well. These numbers are apparently rare, being used for specialized machine-to-machine and arctic telephone services. Logically the 666 area code would be allocated for this use, but it has been skipped.

The 456 NPA was briefly assigned to carrier-specific use (similar to 500) but specifically for inbound international calls, but this never seems to have received use other than a service to identify the carrier in use for international calls. Nonetheless, it is mildly interesting that there once existed an NPA that was intended only for use by callers outside of the NANP area.

The 950 exchange code had also formerly had a special meaning to access competitive long-distance carriers, but this was replaced by the 101 "dial-around" codes often referred to as 10-10 numbers. 950 is still reserved as an exchange code today.

Are there any other special telephone prefixes? (besides these and of course 800 and 900, which I plan to and have discussed separately, respectively). One commonly cited example are "test exchanges," exchange prefixes (NXX) that contain only test numbers. I would call these "quasi-standard" in that they tended to be consistent between similar makes and models of telephone switches, so there are common patterns. For example, 222, 958, and 959 are commonly used as exchange codes for test numbers---but just as commonly are assigned to actual subscribers. Ultimately it depends on the switch and sometimes how it is configured. In rare cases, three-digit numbers work for this purpose.

So that's a whole lot about non-geographical numbering. It's interesting that, as a broad trend, non-geographical telephone numbering other than toll free has been consistently unpopular in the US. This stands in contrast to a number of countries where cellular phones are typically numbered in non-geographical prefixes, which makes more sense than our American convention of assigning cellular phones NPAs based on where you lived in 2007. It's just tradition.

[1] I found a newspaper column which criticized it specifically because 710 was the last remaining unused "real" NPA. By real, the author meant an NPA with a 0 or 1 in the middle. For reasons I am not completely clear on, when NPAs were first assigned by AT&T, the middle digit was 0 for all NPAs which originally covered an entire state (e.g. 505 New Mexico, 503 Oregon), and 1 for NPAs which covered only a portion of a state (e.g. 212 New York City and 315 upstate New York). This scheme was abandoned as of the first NPA splits, since having to renumber the area covered by the new NPA was unpopular enough without having to renumber the old NPA as well to turn it into a 1 middle digit. That said, for many years most new NPAs retained a 0 or 1 middle digit.

[2] This isn't actually a footnote to anything, I just wanted to say that the listing of all assigned 555 numbers includes a range assigned to "Craig 'Tax Freeze' Freis", who would later run for president. His platform was his middle name.

>>> 2021-02-11 the third and up broadcasts

In my RSS reader, I came across the article New Life for the Third Network on the North Korea analysis blog 38 North. I've always been interested in this system because it is an unusual broadcast technology, and it seems it might remain relevant as Kim Jong Un has apparently called for the apparently dilapidated system to be repaired and expanded. What I'm saying is that I don't just write about obsolete technology, but also foreign policy, apparently.

Anyway, onto the obscure technology. If you're not familiar, the "Third Broadcast"[1] is a wired radio system installed in at least some cities in North Korea. Rumors about the system abound, but I will try to stay to facts, which there are very few of. The system is evidently operated in a similar fashion to a radio network with central programming produced in Pyongyang with various slots filled in with programming produced at a regional or local level. The "receiver" consists of a speaker unit with a volume knob that usually seems to be plugged into a socket on the wall, but might sometimes be hardwired (or the plug concealed behind in a recess socket). There is only one channel, so the volume control is all you need.

Technically, one wonders, what exactly is "wired radio?" Well, there are various systems that have been referred to as "wired radio" or "wired broadcast". The term is usually reserved for systems that do not function by transmitting RF into a coaxial cable, because, well, we usually just call that cable. Instead, "wired radio" systems usually don't involve "radio" at all but just directly put the modulated signal onto a wire.

From what little I have been able to figure out, my guess is that North Korea's example is basically a large-scale 70v audio system. High-voltage audio systems are fairly common in commercial overhead paging and some sound reinforcement applications. Basically, the low voltage and high current produced by a conventional audio amplifier requires a very large-gauge wire to span long distances without significant loss, and large-gauge wires are expensive. If you want to install, say, in-ceiling PA speakers throughout a building, you can save money by using a special paging amplifier which produces a high voltage and low current.

Typically in these systems the speakers are just normal four or eight ohm speakers, but each one has a transformer mounted to it that converts the high-voltage audio to low-voltage at higher current for the speaker coil. You can also fit the individual speaker with a volume control using a simple potentiometer, although since paging systems are not usually meant to be adjusted "on the fly" this isn't especially common, with it being more common for there to be multiple taps on the amplifier or an internal adjustment knob so that the installer can do a one-time adjustment for roughly equal loudness throughout a room [2].

There are a couple of different conventions for these systems, but by far the most common is 70 volt. For a large-scale system like that in North Korea, they may use 110 volt, which is also used in some commercial buildings. I'm not sure how exactly this scales up to a city, do they use yet a higher voltage for longer distances with neighborhood step-down transformers? In any case, high-voltage audio is a well understood, commercially available technology that would be quite consistent with what I've seen of the North Korean system.

That's not to say that I'm sure this is the case. There are other ways of distributing audio over large areas. The Muzak company, for example, got its start by distributing background music to clients using a wired network. As I understand it, the first implementation of Muzak used leased telephone lines (presumably "toll quality" lines for better audio) to get the sound to each building, where there was an amplifier to high-voltage audio for the building's speakers. This was done at a time when recorded music was not common, so the background music in large stores was sometimes actually a live performance--- just performed elsewhere. North Korea might use a similar arrangement to feed neighborhood amplifiers.

My assumption that North Korea uses a high-voltage audio system rather than a low-level signal distribution network is due to the fact that the radios are only connected to a single socket. They don't seem to require power for amplification, so the audio must arrive already amplified. I'm not aware of any good way to do this other than high-voltage audio.

So, is there any other interest I can eek out of high-voltage audio? Of course! Another common application of high-voltage audio technology, which is basically just a special case of paging, is audio masking systems. These are typically used in facilities where sensitive discussions occur in order to prevent eavesdropping, and vary in sophistication. A therapist's office might use a simple white noise machine to prevent casual eavesdropping from the waiting room, while a facility housing corporate or government secrets might use a wide-area sound masking system intended to be resistant against technical surveillance. These larger-scale sound masking systems are often essentially just 70-volt PAs used to broadcast white noise, but the "speaker" designs tend to be a little more eccentric.

That's because high-end sound masking systems often use transducers coupled directly to surfaces in order to prevent the capture of audio from the surface by mechanical or optical means. That means, for example, an audio transducer adhered to each windowpane which vibrates the windowpane with white noise in a way that is minimally audible to humans but should be overwhelming to a laser reflection listening technique. Atlas Sound is a major manufacturer of these high-end systems and their products run surprisingly cheap on eBay, I have a TSCM-grade sound masking unit under the bed because I think it helps me sleep, or at least improves the security of my dreams. They also manufacturer sound masking speakers intended for use in air ducts, plenum spaces, transduction to doors and walls, etc. Putting Muzak into such a system might have an amusing result, as all these untuned surfaces would probably rattle and resonate in horrifying ways.

A similar wired radio system to North Korea's existed in the Soviet Union, which might give the impression that wired radio is limited to troubled Communist states. That's not entirely true, but it is certainly more attractive to embattled regimes because it has the property of being extremely difficult to intercept or disrupt (jam) compared to broadcast radio. That said, there have been other wired radio schemes with little to do with state propaganda. Well, depending on what you think of the BBC, I suppose.

Indeed, one of the other cases of a "wired radio" technology I am aware of is the television system in Kingston upon Hull, England. As I understand it, the mid-sized city of Hull is built on geography that made television reception extremely uneven---too many hills and gulches for good coverage. In the 1930s, a company called Broadcast Relay Service operated "piped TV" so that Hull residents could get their television without struggling with reception. This might sound like it's just cable television, and conceptually it's about the same, but the implementation was quite different.

Broadcast Relay, later called Rediffusion, actually used sets of twisted pairs, one to carry each channel. A specially equipped television had a switch box that connected a different pair to the CRT depending on which channel you wanted to watch. This was perhaps technically simpler, but less scalable, than cable television. The scalability problem would not have been evident at the time, because there were very few television channels in the UK, very far into the modern day. My recollection is that a typical Broadcast Relay switch box supported four channels.

The funny thing is, post-war, Broadcast Relay rebranded as Rediffusion and went into the radio business---wired radio. They operated an audio-only service nearly identical to the Third Broadcast, except that homes were connected with multiple pairs for multiple channels. They expanded into various British colonies and other UK cities, and transitioned more into the television and radio rental business... This sounds odd to a US audience, but apparently in the UK it was very common to rent your television and radio.

Of course, by the '70s these wired services had become uncompetitive with the improved broadcast technology and Rediffusion went the way of history, trying out a variety of diversified businesses that never caught on.

I'm not aware of any successful wired radio services in the US for general public consumption, although I would not be at all surprised to learn of one. Similar technology was widely used in the US but generally for background music applications, as in the case of Muzak. Many of these services transitioned over time to other, less-expensive distribution networks like FM subcarrier, mailed-out recorded tapes, and satellite. Of course, today, I assume most background music is done by IP, but I bet there's still at least one chain that uses a hired satellite transponder to distribute music to their stores.

Earlier in the history of telecom, it was typical for major cities to have dedicated wiring run to major businesses for all sorts of specific purposes. Over time, most of these systems moved to leased telephone lines, then to dialed telephone lines, and onto the internet. This could be viewed as the long-term component of the trend of "over the top" or OTT services. Today we talk about telephone and television being OTTd onto internet services, but post World War II they were basically talking about OTTing background music and fire detection onto the telephone system.

And perhaps that leads to another topic: in the not too far future, I will talk about fire telegraphs and their function as perhaps the earliest urban-scale digital communication system. The need to quickly dispatch fire brigades has long driven innovation in telecom, and the fire telegraph is an elegant design which has an ongoing influence today in both fire practice and, well, a few places that just still have fire telegraphs.

[1] Yes, 38 North calls it "Third Network." I think these are both possible translations of the same Korean term, but "Third Broadcast" is generally more common. This refers, I suppose, to it being third after radio and television.

[2] Once, in a church, I dealt a bit with an audio reinforcement system that ran at high voltage and had wall panels with volume adjustments for each room. It also used multiple runs to each room to enable a simple matrix arrangement. This was a system installed in, I would guess, the '70s, and I don't think this kind of setup is common today. Last time I had the opportunity to deal with a commercial paging system it was a brand-new one that just used an IP network to link separate paging "nodes" with integrated amplifiers for each zone. It was hilariously complicated and less hilariously expensive.

>>> 2021-02-08 a video

A bit behind my intended schedule, but I've put up my first effort at a video. You can watch it on YouTube at https://www.youtube.com/watch?v=RKbfNfY8kyA, and I'm going to get it on a PeerTube instance as well I think.

There was a bit of an unexpected shift in topic, just based on my interests over the last week, so rather than environmental remediation the video discusses nuclear EMP simulators built at Kirtland Air Force Base.

The video is frankly not great, but I learned quite a bit from making it. For one, I need to improve my audio setup a bit, apologies for the clipping and room echo. In general, I will probably also make future videos a little more scripted. This was basically just the kind of lecture I would give in person but to a camera, which is relatively easy for me to make but leaves it feeling unpolished.

Finally, in what I can only describe as a real dumb move, I accidentally had the screen recorder set to a very low bitrate (left over from some testing I had been doing of some real-time video streaming stuff...), so every time something moves it takes a second for the image to resolve. Lesson learned about proofing the recorder output before I spend three hours talking into it.

In any case, I hope you find it interesting, and I'm going to be working on getting better at this.

I also spent so much time on the video that I didn't get a text post together over the weekend like I normally would, but I'll try to get one out later this week. I am taking my private pilot checkride this upcoming weekend so it's a little bit crazy schedule-wise as I'm cramming practice on some maneuvers. Wish me luck on the short-field landing.