The Gadget We Miss: The US Robotics Courier Modem
The king of dial-up was a modem that could handle anything you threw at it
It begins with a a short burst of two-tone sound at 1375 and 2002 Hz. In response, a burst of sound at 1529 and 2225 Hz, which gets the conversation going. Through a set of query and response tones, the two sides of the conversation agree on how to talk to each other, who gets to speak when and how quickly they can talk…
You might not recognize the technical description, but anyone who used the Internet before the year 2005 will instantly recognize the sound: the noises of a dial-up modem negotiating a connection when the other end picks up. (For a more detailed explanation of what these noises actually mean, see the excellent breakdown of how this conversation works by noted hacker Oona Räisänen).
The idea of the modem (short for modulator-demodulator) dates back to the beginning of the 20th century, when people were trying to work out how to send digital signals through the analog telephone network. The telephone network had been built to carry human voices, which are still understandable if you have pops, crackles and other noise on the line. Digital signals can’t survive those, so the first modems took a digital signal and modulated it into an audio signal that could be sent over a crackly telephone line. At the other end, another modem picked up the modulated signal and reversed the process, recreating the original digital signal. This meant you could use the telephone network to send data, which was much cheaper than running a dedicated cable.
By the mid 1970s, these systems had become more sophisticated, offering features such as error correction and automatic speed selection, where the two modems on either end of the connection would agree on a speed to send data, based on the quality of the phone line. If the quality of the line was bad (due to factors, believe it or not, such as if a bird sat on the telephone wire or if it was raining), the two devices could slow down, working together to find a speed that would enable both ends of the conversation to send and receive data correctly.
This happened alongside the microcomputer revolution of the late 1970s and early 1980s (which gave rise to home computers like the BBC Micro), and it was inevitable that the two would connect. And they did, with the explosive growth of online services like Compuserve and AOL. Home computers used modems to connect to these services, and later, to the Internet.
If you want to get a sense of what the state of the art of the Internet and dial-up was in 1985, watch this episode of the Computer Chronicles.
US Robotics (also called USR to avoid confusion with the company from the SF classic I,Robot and the 2004 film) was founded in 1976, and launched their first modem in 1979. Following the break-up of AT&T in 1984, they started selling modems to the public. Previously, equipment that connected directly to the phone network had to go through very expensive testing that only big companies could afford. After the breakup, this testing became cheaper and easier, so smaller companies could sell equipment direct to the consumer that plugged into the phone line. The first US Robotics Courier model came out in the early 1980s, offered to professional and academic users. Where it really found a niche, though, was with BBS (Bulletin Board Systems) Sysops (System operators), who hosted their own computer systems in their home and let users dial in to send and receive email, grab files and play games. The network that many of these used (called Fidonet) will be the subject of a future article.
Although some users claimed allegiance to another modem manufacturer (like those tricky upstarts at Telebit, or the more corporate Hayes), the great majority of those who wanted their systems to work despite the vagaries of the analog telephone network went with the USR Courier, because it could handle pretty much any kind of connection, and kept on working for call after call. For a busy BBS run by an enthusiastic (but often tired) Sysop, being able to handle more callers without downtime made your BBS more popular, and made it worth the expense. In this 1995 conversation on Usenet about the best modem for a BBS, the consistent answer is the Courier, because of reliability and the discounts that USR gave to Sysops.
“Just get the Courier, you will NOT be disappointed, it is excellent.”
This marketing ploy became more important in the late 1990s, when a number of rival standards for modems were developed that increased the speed of data transfer. USR developed a technology called HST (High Speed Transfer), which was available only on their modems. If the BBS had this technology, downloading data from the BBS would be quicker, up to a then radical 16.6kbps. Modems from other manufacturers couldn’t speak this high-speed language, so they would download slower. In the mid 1990s, USR did it again with a technology called X2, which was a rival to the K56Flex standard developed by other manufacturers. Both of these standards could download data at up to 56kbps, the maximum speed that the telephone network could handle, thanks to the limits of how much data can be squeezed into a telephone signal (see Shannon’s Theorem)
Eventually, the manufacturers got together and agreed on a standard called V.90 that would be compatible across all modems, and USR came out with a Courier model called the Courier V.Everything which could handle V.90 and all of the variations that might be present on older modems.
“It’s not just about speed. It’s about stability, reliability (we leave
ours on 24/7 for years at a time), and upgradeability.”“…once you have used a Courier, nothing else is a
modem in your book at any price.They are the very best there is.
I have connected with mine where other modem I have have failed.”
Usenet conversation on the value of the V.Everything Courier
Another curious aspect of modems is that they were smart devices, controlled by small computers that oversaw the communications process. These were controlled by commands called AT commands, short for ATTENTION, that were first developed by Hayes in 1982 for their first smart modem (and are known as the Hayes Command Set). These AT commands grew in complexity as the modems got more sophisticated, and you needed to know at least some of these commands to get the most out of your modem. However, some manufacturers interpreted these commands differently, so the process of getting a modem to work often required some research. At the basic level, you could make sure the modem was working with an AT command, then make it dial by sending the command ATDT followed by the phone number:
AT
OK
ATDT155512345
RING
CONNECT 38400
Some setups required more complex commands (usually called the initialization string) to get the modem running, and these often became long and complex, like this one for the USR Courier V.Everything modem:
AT&F&B1&H1&K3&R2S56=128&N12
There is a comprehensive list of initialization strings for modems from all manufacturers here if you are trying to get an old modem working.
Although modems were getting faster in the 1990s, the seeds of their destruction had already been sown. The telephone network was digital by then, and new ways of sending data over the phone line such as ADSL (Asymmetric Digital Subscriber Line) were becoming available which could offer broadband speeds that made the. And they also had the benefit of allowing voice calls to be made at the same time, so you were not tying up the phone line whenever you called AOL.
So, the modem became redundant when broadband became common, although it still has a certain following. USR (who became part of networking giant 3Com, and was then spun off in 2000) still makes and sells the Courier modem, marketing it to businesses that want a secure way for employees to connect to their corporate network. And there are still those that have to connect to the Internet over a dial-up connection: a recent report by the Pew Internet trust claimed that 3% of US internet users are still using dial-up, either by choice or because broadband is not yet available to them.
So, although modems are not the important part of the computer experience that they used to be, they are still useful. And the USR Courier modem is a gadget we miss, because it helped to enable the BBS revolution and to get a generation of computer users online.
Do you have memories of your modem? Add a note to this story, or you can post your own memories of dial-up days to Medium.com. You can find out more about the glory days of BBSes in the excellent series by Jason Scott BBS: The Documentary.
