Retrotechtacular: Tom Carter Revolutionized Your Phone

It is hard to remember, but there was a time when you couldn’t hook much to a telephone line except a telephone. Although landlines are slowly falling out of favor, you can still get corded and wireless phones, answering machines, and even dial up modems. Alarm systems sometimes connect to the phone system along with medical monitoring devices and a host of other accessories.

All of that’s possible because of a Texan named Tom Carter. Tom Carter was the David that stood up to one of the biggest Goliath’s of his day: the phone company. The phone company had a legal monopoly on providing phone service. The reasoning was that it didn’t make sense to have multiple competing companies trying to run wires to every house and business in the country. Makes sense, right?

Hush-a-phone_pedestal_modelIn the early 1920’s a company called the Hush-A-Phone Corporation started selling a simple device. It was more or less a cup that slipped over the mouthpiece of a phone temporarily. It made your conversation a little more private and also cut out some background noise from your calls. The device is pretty unassuming as technology goes (see picture to right).

By the late 1940s, the phone company decided that if people were attaching devices to their phones, the phone company would terminate their service. Keep in mind that the device didn’t make an electrical connection. It was just an empty box that fit over the telephone transmitter (or microphone, if you prefer).

Late in 1948, Hush-A-Phone protested with the FCC, but the FCC decided to open the case to public comment. By 1949, the company had sold about 125,000 devices. In 1955, the FCC decided that you could not attach a Hush-A-Phone to your phone because it might cause a deterioration in phone service (despite technical reports that the Hush-A-Phone did not impede phone operation).

Although the FCC’s decision was final, Hush-A-Phone appealed in court. Late in 1956, a Federal judge decided that it should be up to people how they want to use their phones as long as it didn’t affect the public. Particularly since a phone user could simply cup their hands around the phone for a similar effect. As a result, the sale of the device continued up to about 1972. You can see a video about the Hush-A-Phone from the American Museum of Radio and Electricity , below.

What About Carterfone?

The problem with the decision is that it only required the phone company to allow specific devices to attach to phones. If you wanted to make something similar, you had to get the phone company to agree to it. If they didn’t, you had to go to court against a giant company.

Carterfone_cradle_at_CHM.agrTom Carter started selling the Carterfone in 1959–three years after the appeal court ruled for Hush-A-Phone. The device was simple by today’s standards (see photo on left). It was a way to acoustically couple a phone to a radio so that people on–for example, oil rigs–could talk to people on a regular phone.

Taking the phone company to court is a daunting prospect, but that’s what Carter did in 1965. Keep in mind this is about the same time companies are starting to use computers and there is a demand for modems. You could lease a line to use with a modem, but the phone company would not allow data on the voice network. Remember, one way to afford a very expensive computer was time sharing–allowing different users to share the computer and split the costs. However, having to lease lines between users drove up the cost even further. But everyone had phone lines.

By 1966, the FCC realized that it was vital to connect computers via the public phone system. They would hold a  public inquiry on the matter and used the Carterfone issue as a way to revisit the policy of not connecting anything to the phone system.

In 1968–following a seven-day hearing–the FCC required the phone company to allow devices to connect directly to the phone network as long as they did not cause harm to the system. Once the phone company filed a new tariff, Carterfone settled their 1.35 million dollar lawsuit for $375,000

Also in 1968, a company called Codex introduced the first 9600 baud modem. The 125-pound device had 66 PC boards and required tuning to work upon installation and any time the phone line changed. A pair of modems cost about $46,000 and required special cooling, like much of the gear in those days.

Data Access

This still didn’t open the floodgate to third-party phones and devices. The phone company still required you to connect a “foreign” device (meaning one not from the phone company) via a Data Access Arrangement or DAA. The DAA prevents excessive signal levels on the line, protect against voltage surges, and perform other interface features. Guess where the only place you could lease a DAA was? The phone company.

This stood until 1976 when the FCC allowed private equipment to directly connect if it could pass certain FCC tests. Devices received a registration number to show they passed the test and this was the death knell for the DAA.

With an avenue to produce equipment that directly connected to the phone system, the market exploded with new products. Some were innovative like reliable answering machines and cordless phones. Others, like the phones that could send a still picture to a similar phone over the course of a few minutes, didn’t catch on.

By the way, the interface circuit is still called a DAA, but you don’t get them from the phone company anymore.

You may not even have a landline anymore. But if you do–or you just appreciate technical innovation–you can thank Tom Carter.

Photo credits:

Hush-a-phone by [Marcin Wichary] (CC BY 2.0)

Carterfone by [ArnoldReinhold] (CC BY-SA 3.0)

39 thoughts on “Retrotechtacular: Tom Carter Revolutionized Your Phone

  1. If you are ever in the vicinity of Bellingham, Washington*, visit the American Museum of Radio And Electricity. It is absolutely amazing place. Their website does not do their collection justice. Many one-of-a-kind exhibits – where the piece you are looking at literally is the only one remaining in existence. The largest privately owned Tesla on the west coast. Original laboratory equipment from the dawn of radio.

    * Bellingham, Washington in the northwest corner of Washington State, about 28 miles south of the Canadian border, on I-5. Bay Street is not that easy to find. Take the Lakeway Street exit from I-5, turn west, down Holly Street, through downtown, and hang a hard right hand turn where Holly changes from one-way west to two directions.

  2. The acoustic coupler modem was a clever work around the connecting things to the phone network rule. And was a direct descendant from the Hush-a-Phone.

    In 1983 when working at Radio Shack we were quite proud of the phones we sold. The regulation said you had to be able to drop the phone from a height of 6 feet and not damage the phone line. Our extension to that was that you had to be able to drop the phone from a height of 6′ and not damage the _phone_.

    That sold a few phones.

    1. By the time I started working there in 1989, we weren’t proud of much of anything we sold, except maybe the big screen TVs (we were a test store for an appliance sales program that never took off, consequently we were the only RS store around that had a 32″ CRT TV at the front of the store, an impressive sight indeed in those days), and the Mach III speakers that caused us to get complaints from the store at the other end of the mall. Perhaps I was playing my Metallica a bit too loud, but it was a slow sales night. :D

      1. I worked there from ’96-’99 and despite surviving all of the stupid mandatory “training” sessions (read, “here’s how to con someone into signing up for a Sprint PCS cell phone”), never got a pin or anything else beyond a paycheck. Still have my namebadge somewhere though. I don’t think we were proud of anything, other than everyone’s individual pride in being their own special version of a misfit (I include myself in that!). To our geeky little minds, it was at least a little better than sacking groceries. It was an odd time, for sure. Sales goals were meaningless if you had even a shred of a conscience. We spent more time warning other stores in the area (and them us) about corporate mystery shoppers coming through than we did doing much of anything else.

        The highlight of everyone’s day was when it was the beginning of a new month and the “Radio Shack Television Network” VHS tape would finally be swapped out for a new one. This joy lasted for only a few repeats before that new tape lost its lustre as well, but for a couple hours each month we experienced what could loosely be defined as happiness.

        I feel bad for our store manager most of all, bless his heart, as he had to be the first line of defence against the corporate crap, and deal with a rough home situation, and put up with a ragtag bunch of employees. Had he not been through many years of coldwar SIGINT in some forsaken neck of the North Pacific, I don’t think he would have had the patience to put up with the job (or with all of us). I hope he eventually ended up somewhere more worthy of his skills and abilities.

        We did sell a surprising amount of POTS-related stuff though, people knew us to be a destination for that and batteries, and they were still willing to wade through all the “Sprint Store” displays and the Compaq demos in order to purchase from us. I don’t think any of us realized at that point that we were simply coasting by on the fumes of goodwill left over from prior generations. Glad I never bought into their Employee stock purchase program.

        1. Very interesting read. Thanks for sharing! I have always had a love/hate relationship with Radio Shack. It was the only place to buy anything that resembled electronics in my small hometown, but they gradually stopped selling anything but the most over-priced of consumer garbage. What a sad corporate history.

        2. me, I managed top ten sales in my region but repeatedly got called into disciplinary meetings because my “harass customers for mailing addresses so we can physically spam them with fliers” count was way too low. And some jackhole in other stores, had abused the “fake” accounts too much so we couldnt get away with it anymore. Wasnt gonna p*ss off my customers, older people who made my good sales numbers, over spam ads.

    2. Worked there from ’86 to ’96 and had the “sapphire” pin to prove it.

      The only think I was proud of was my staff who could do a full inventory in about five hours, and have less than a page of re-counts.

      1. Ditto on the inventory – my stint was from 1981 thru 2007. Lots of good times, some bad times toward the end.
        I had HD going in my store before anyone else using a satellite receiver and a HD compatible projector (no a stocked item, but I had a special-order returned). Also bought the first personal computer in my town around 1978 (TRS-80). As the article states – telephone equipment sales exploded, and customers drove right to Radio Shack to buy them… and CB radio, car audio, PCs, STA-2100D receivers, BIG speakers, scanners, etc.etc.Those were fun times…

        1. Similar story. I worked there from ’81 to ’83. They hired me straight out of high school, just turned 18. That was very much against their policies, but I was the owner of a TRS-80 model I serial number #000020, and a CoCo serial number #000004 and quite the expert on them. Still have the CoCo.

  3. Thanks, Tom!

    9600 bps modem in 1968 though? With a million boards and it weighed the same as an elephant? Got any pictures, articles? They didn’t re-invent 9600 til the late 1980s, why were there decades of 1200/75 300/300, when 9600 had already been done?

    1. The decades of 110/300/1200/2400 were about:
      1. acoustic couplers (450 was the max you could put through a handset, IIRC)
      2. full duplex over dialup (as opposed to half duplex, leased line) — a MUCH more challenging task
      3. doing it without the benefit of cheap DSPs (Hayes 1200 baud did it first, IIRC)
      4. I remember 9600 FDX with a GDC (General DataComm) big grey box, abt the size of two laptops, stacked, in 1990

    2. Cheap DSPs and telecom ASICs made higher speed modems possible.

      Also I’d guess that there was no way until the ’80s for a device on the line to ask the phone company to turn off the voice filters and echo cancellers, which was also required for v.32.

    1. The GPO (General Post Office), a government-owned company, built our phone network. Except in Kingston Upon Hull but that’s just an interesting exception.

      It was built out of tax-payers’ money, then the phone part was separated and sold off to private investors in the 1980s, making vast profits for the investor classes. The money went to tax breaks for rich people. Similar things happened to British Gas, British Rail, and the various Electric Boards, the Water Boards, etc. Since British Rail was privatised, fares have gone up and quality has fallen. Same with the Water Boards. Lack of investment, in favour of return for shareholders. And the rest.

      In recent years, disabled people in Britain have been found starved to death, in houses with the power cut off. Money obviously didn’t trickle down their way.

      There are groups, now, calling for the re-nationalisation of the rails and some utilities.

        1. Oh OK, I was talking about the monopoly aspect.

          Yes, in the UK stuff had to be BABT approved before connection to the phone line. This meant modems cost extra. At some point around 1990 the law was changed, and now you can plug anything in without it requiring approval.

          It was news to geeks at the time, because it meant more, and cheaper, modems. Prior to that I remember one modem advertised, full-page, that specifically didn’t have BABT approval. The ad pointed out that BABT approval was silly, and that this modem was great and super-low priced (and it was very cheap compared to others). It was legal to sell the modems, the crime would be the user plugging it in.

          1. and thanks to the monoploy aspect we are stuck in a rut with broadband with respect to the last mile. The sub company of BT called OpenReach (ironic) control the last mile and thus the competition making it prohibitively expensive to get things done. So many places (like mine) have fibre to the cabinet, but a further km of crappy old wires and openreach have no reason to upgrade this becaseu no competition for speed of services means they can sit on their hands doing nothing.

            Coupled with that in the UK we no pay double for the rental of the phone line than the ADSL or fibre service that runs on top of it. And many people have no need for a POTS line or a dialtone.
            But the monopoly has to keep all of that legacy equipment going that they inherited as a windfall back in the day.
            Once upon a time you could just rent a pair of wires from one location in a town to another for private comms, but I believe no more.

      1. Oh dear, Greenaum is clearly too young to remember – or perhaps phoning in from a parallel timeline. The British Post Office telephone system was a horribly under-invested, madly over-priced government monopoly. For much of the country it relied on pre-WW2-type electromechanical exchanges… in 1980. Their digital replacement was horribly late. Using a phone other than the one the Post Office provided certainly wasn’t allowed. Many were hard wired anyway, we couldn’t even move ours away from the wall the wire came in at. When the phone service was privatised, the deal for the investors was more or less “you get to milk this, if you upgrade it”. As BT, the privatised phone co raked in a lot of cash even though the real cost of calls and line rental fell quite a bit over the next decade, but they also replaced a huge amount of exchange and trunk infrastructure with more modern stuff, pouring in the investment needed to make the digital exchanges work. By the time modems became widely available in the early 90s, the phone system was able to cope with them.

        Sad though it seems now, it was actually pretty exciting when the newly-privatised phone co sent a man round to take away the Post Office’s old brown rental phone and replace it with a socket that let you plug in a choice of alternatives, along with this strange novelty… a pushbutton phone. At first BT allowed third-party equipment if it had an expensive certification provided by a puppet of theirs, though non-permitted-but-still-worked uncertified modems were available mail order “for use on private telephone systems” and nobody ever checked. Sometime in the middle 90s they were made to lower the cost of that certification so modems got cheap just about in time for the dialup internet boom. Anyway privatisation was the answer to “how do we get the investment to fix this mess nationalisation made”, and for the phones it worked pretty well. Sure, NOW they’re dragging their feet on upgrading beyond basic broadband (partly because in most areas they have a cable rival that is the higher-cost, higher-speed alternative so take-up’s not a given) but this really only matters if you’re permanently vegging out consuming HD video rather than reading and code, and I don’t see why anyone should subsidise that.

    2. Just like the US and UK, Australia’s phone system was a monopoly run by first the PMG (Post Master General) then Telecom Australia, and finally Telstra. *Nothing* could be connected to a phone line without Austel approval (I don’t know the details of Austel, but I think it was a subsidiary of Telecom Australia).
      Part of the “line subscription fee” was leasing a phone from Telstra/Telecom, and even if you didn’t actually have a phone supplied by them, you still paid. You had to specifically apply to have the charge removed from your bill (and hand in a phone – which could be easily found at the local tip because they were so cheap and low quality).
      There were restrictions on multiple phones on the one line (extra fees applied), and until sometime in the late 80’s there was no way you could (legally) connect a modem to the phone line. Same deal with security systems – big fees applied, even though it was just a standard line.

    1. Nah, otherwise why haven’t many people bought phone scramblers once it became legal to connect them? I’m sure if you were a spy, you’d get your screwdriver and wouldn’t care what the phone company thought. Pure monopolism is a good enough answer, forcing people to lease phones at great profit, when a phone can be made for next to nothing.

      I’m sure Bell had plenty of friends in Congress even back then.

  4. I’m surprised you didn’t mention FCC part 68 by name. Essentially part 68 compliance involved a 600 ohm isolation transformer between the telephone line and the device connected to it. There are other things, typically MOVs and such, part of the circuit too.

  5. This reminds me of when I was importing 1200 baud down/300 baud up modems into Malaysia in the early 80’s and thought 1200 baud was fast! I still have a 300 baud acoustic coupler for my TRS100 laptop (that still works). When talking about modems it is also probably worth noting the impact of DTMF on the ability to control thgings remotely. My first home control system used them and hacking them is how Jobs started out.

  6. Nowadays, you have the cell companies charging you extra to start a hotspot on your phone. As if it makes a difference whether I stream music directly on my phone or from another device networked to my phone.

    1. Is this going on? I don’t really use a smartphone, but I can imagine someday people will just connect some simplistic circuit with couple of transistors photo- and laser-diodes and power supply directly to an ethernet cable, with cheap halved binoculars on one end, and switches/routers/computers on the other and make their own mesh network with accounting protocol for cheap internet sharing… then just install the optical links on window sinks on the floors above ground floor… like Uber of ISPs but then without a replacement centralized company as the new middleman…

      1. Been done, about 15 years ago, called RONJA. Uses IR or red LEDs and cheap optics for line-of-sight connections of around a mile. Hasn’t really been improved much, since then, so it’s pretty slow by modern standards.

  7. Back in the day of Ma-Bell you did not own the phone, AT&T did. Nor the wiring in the house. AT&T installed and owned it all. Thus they were not open to outsiders installing anything on THEIR equipment. If the phone/system didn’t work AT&T came out and fixed it, no charge. All part of the service.

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