I know what dial-up is, but how does a voiceband modem work? Why would you hear all those noises when you were establishing a connection and when you lifted the phone from the receiver? Is it representing binary bits as sounds, transmitting them through phone line as electrical signals, and then it demodulates the electrical signals? If DSL also uses sends and receives data from a phone line, why is it much faster? And why isn’t it possible to access sites such as Netflix and YouTube using dial-up?
Also, how was online gaming with dial-up, and BBS? What was different about bulletin boards from the '80s and '90s and the bulletin boards of today?
I don’t know what ELI5 is, but acoustical modems used modulation techniques like frequency-shift keying (FSK), quadrature amplitude modulation (QAM), and phase-shift keying (PSK). You would hear that stuff because it was going down the normal phone line, which was filtered for voice frequencies, unlike DSL which used much higher frequencies and bandwidth. (Actually, I have never tried listening into a naked DSL line, huh…)
Anyway, you can access all the sites but your bandwidth will be limited, I don’t think you’ll be streaming too many high-definition videos at 1200 baud. That should give you an indication of the difference in online gaming between the 1980s and 1990s and today, though games like Doom and some others supported multiplayer even if you didn’t have direct access to the Internet. Plenty of text-based multiplayer games of course. Also all the bulletin boards were mostly conducted text-only for the same reason, downloading images or other binaries took a while. Web browsers did not appear until the 1990s either.
In that case, for a good answer I’ll have to compose a longer explanation or leave that up to someone else, but for starters these pictures might help:
In FSK you encode bits by changing the frequency of a carrier signal:
Basically like your FM radio.
For phase-shift keying you mess with the phase instead:
e.g. here is some binary phase-shift keying:
For QAM you basically modulate both the amplitude and the phase at the same time: You can think of it as modulating the amplitude of two carrier waves that are 90 degrees out of phase:
Acoustic couplers were used to take advantage of the ordinary phone user interface, a microphone and speaker in a telephone, in order to transmit data. Modems are devices which directly connect to phone lines to transmit and receive data.
Until the 1950s acoustic couplers could not be used without the permission of AT&T. That changed following a lawsuit, and a decade later as the result of another lawsuit modems were allowed to directly connect to the phone lines so long as they met requirements specified by AT&T that would prevent damage to the phone system.
One should also make a distinction between the earliest dial-up modems, which used acoustic couplers, and the later ones which connected directly.
The acoustic coupler style modems were the first and the slowest, and involved inserting a telephone handset into an appropriately shaped receptacle with two rubber cups. Those were the ones that we typically associate with the whistling and beeping sounds of old dial-up modems. They had the advantage that you didn’t need to connect customer equipment directly to the phone network, which back in the days of Bell monopoly was prohibited. They had an upper speed limit of around 1200 baud, but I don’t personally remember any that were faster than 300!
Faster dial-up modems became possible with direct-connect type modems which quickly superceded the acoustic couplers. These increased speeds over time as technology improved, eventually becoming as fast as 56 kbps, at least in theory, on a good day, with a really really clean connection. But with anything less than an absolutely optimal connection, they would quickly fall back to much slower speeds.
The reason DSL is so much faster is that all the above types of dial-up modems, direct connect or not, could only work by modulating a voice-grade carrier, which was inherently very low bandwidth. They were sending digital signals, but over a low-bandwidth analog medium, which was the only kind the telephone network could handle. DSL, OTOH, involves all-digital signaling, between a DSL modem on the customer premises and DSL equipment at the telco end. It’s limited only by the signaling technology that can be deployed on the physical copper wires.
You’re right about Bell and AT&T prohibitions on direct connect, but I suspect you accidentally got this backwards. Because of those restrictions, acoustic couplers for a time were the only modem type that customers could use. When those restrictions were dropped, direct-connect modems became possible and eventually became very much faster than the acoustically coupled type.
Since the OP is young I’ll point out some things about the past that would not be obvious today. AT&T had a monopoly on the phone system in this country. Outside of a few local exchanges they owned all the phone lines, and all the telephones directly connected to them. You could not buy your own phone and plug it into the wall, you could only rent telephones. Phone lines were constantly monitored for the presence of unauthorized equipment.
Right, got the wording wrong there. You could use only acoustic couplers unless a specific device was approved by AT&T. Once a standard was set anyone could use a modem that met the standard.
Also, as to timeframes, according to the article on acoustic couplers I linked above, the changeover to direct connect didn’t happen until the mid-80s: “Prior to its breakup in 1984, Bell System’s legal monopoly over telephony in the United States allowed the company to impose strict rules on how consumers could access their network. Customers were prohibited from connecting equipment not made or sold by Bell to the network.”
I’m not sure what they are referring to, the Hayes Modem was available earlier in the 80s, and the requirements for modem devices had been specified. You could also buy and connect your own phones and answering machines prior to 1984. I think as a result of the break-up they no longer had control of the standards.
A non-technical answer, because I think that’s what you’re looking for.
Dial-up was slow. And by slow, I mean sloooow…
It could take a couple of minutes to download a single image, and not a particularly hi-res image by modern standards.
Video of any kind was simply not possible at those speeds.
Bulletin boards were text based. i.e. a black background with 24 lines (typically) of white text on it. If it had colored text that was pretty fancy. You entered commands like you did with DOS command lines (not sure if you know what that is).
You mentioned “until the 1950s …” and obviously the transition to direct-connect modems came much later than that, since consumer modems themselves came much later. There was indeed a landmark case in 1956 which started the long and gradual process of allowing customer-provided equipment. But remember that modern modular phone jacks didn’t become widespread until the latter part of the 1970s. Earlier types of jacks (the old four-prong types) existed and were in limited use, but until modular jacks became widespread and eventually universal there was no practical way to use a direct-connect modem even if it was allowed. From my shaky recollection, acoustic couplers remained common at least until well into the 1970s.
Dial up was so slow that you could read a book and surf the net at the same time. *
Video clips could be downloaded throughout the late 90’s (heyday of Dial up) but those were slow to download and were seconds long. No way Netflix could have existed then.
*I remember one weekend in about '97, my dad clicked on a headline, rose and drove me and my mother to the bakery where we picked up fresh bread and other stuff , and came home to see the site just finish loading. Admittedly the bakery and give minute away and this was a heavy site and net was slow that day but it’s an example.
You could also participate in threaded (text-based) discussions on e.g. Usenet rather than dial into a specific BBS. ETA I mean not in the 1970s but soon after 1980, sure.
One way to demonstrate the limitations of dial-up Internet access is to try using it on today’s Internet.
Even “basic” websites today assume a minimum connection speed on the part of the consumer and as demonstrated in the video I linked, it can take over two minutes just to load the MSN homepage.
Dial-up was all I knew until late 2003 when I entered college and experienced “high-speed” internet via my dorm room. Suffice to say I was blown away.
Speaking of fast changeovers, I wonder how many here remember ISDN, the phone companies’ supposed digital network of the future? What they called Basic Rate ISDN (BRI) would have provided customers with two 64 kbps channels for use with data or digitized voice and one 16 kbps signaling channel, the so-called “2B+D” configuration. ISDN languished for quite a while, and in the meantime Ethernet became widespread, analog modems became nearly as fast as an ISDN 64 kbps channel, demand for communications bandwidth was growing fast, and ISDN was looking obsolete before it had ever been deployed. To their credit, the telcos were already working on ADSL (asymmetric DSL, with fast download speed and much slower upload) but that wasn’t seeing any deployment either.
And then, bang! Cable TV providers started offering broadband internet services over their cable infrastructure. It was unreliable at first and very much slower than even the lowest-tier service, but hot damn! I was an early adopter and got 3 Mbps into my home! It was unbelievable compared to anything any typical consumer had seen before. (Interestingly, my relatively modest internet service today is exactly 100 times faster, 300 Mbps. And rock-solid reliable.)
And almost immediately, the telcos announced ADSL and started rolling it out at record speed! The wonders of competition – something the telcos weren’t used to! And it seemed that every time broadband cable speeds improved, ADSL more or less matched it, in speed and in price. The telcos also started investing heavily in fiber optic infrastructure when they hit the limits of copper.
I remember in the Napster era. (Late 90s-00s ish) downloading mp3s at about 1mb a minute.
Also a lot of multiplayer was either slow, asynchronous or just local. LAN parties were a lot more common, if not as practical.
I remember ISDN mostly because it’s an album titles from Future Sound of London, and a friend played it regularly. No memory of it ever being offered for internet service though
