Why was dial-up ever a thing, why didn’t they use DSL from the start?


Why was DSL not used in the early days of the internet? Did the technology require faster chips that weren’t available at the time?

In: Technology

i think you overestimate the ability of humans to conjure technology out of thin air.

stuff needs to be invented.

an invention is most often an improvement / iteration of previous inventions.

dial up was a thing because it was a simpler technology.

Two main reasons:

1. Dial-up is a simpler tech, by far.
2. Dial-up doesn’t require any help from any ~~ISPs~~ phone companies.

Dial-up works by transmitting audio, which means you could just dial the number of any random person with a modem and establish a 1 to 1 connection without any help from a phone company.

DSL can’t work that way, because it uses frequencies that can’t get through the phone system. It needs some very [special hardware](https://en.wikipedia.org/wiki/Digital_subscriber_line_access_multiplexer) at the end of your phone line. DSL is only possible if your phone company specifically installed a bunch of expensive hardware to support it, and only if your line is suitable for it.

All the infrastructure was made for phone lines. You could only send sound waves no higher then 4kHz in frequency and of limited quality. Dialup would work over this phone network without any changes to any of the infrastructure in the network. It is even still used today in certain situations. With T1, ISDN, ADSL and now fiber you need to upgrade the entire network infrastructure to these standards. You need to replace the phone exchange with new and modern equipment. But dialup did not require any changes. You could technically run dialup over old phone exchanges from the 1880s if you wanted, but you can not do that with DSL. The only part of the phone system you can keep when upgrading from dialup to DSL is the phone lines.

They used existing Infrastructure… and for a pretty long time, that infrastructure was completely mechanical (without chips)! The Internet was only an additional number you could call… The Maschine on the other side was interpreting the tones as bytes and also had to answer…

Easy to implement, easy to integrate

The more people used this early net, the more it has to be scaled… ISDN was in fact only 2 phone lines (duplex, one for sending, one for receiving… double the fun!) Just to send more and faster…

I think this was ok till somewone wanted to browse AND phone someone at the same time… DSL was invented 😉

Any electrical signal traveling through a line can be analyzed as a bunch of different frequencies. Back in the 1800’s, the phone system was originally only designed to carry frequencies corresponding to the sounds humans could hear.

DSL uses extra high frequencies that are too high for humans to hear. This is fantastic because it means it can use the old-fashioned telephone lines, *but* high frequencies die out over shorter distances, meaning a telco that wants to enable DSL has to place its facility closer to the user than before. So the telephone company has to change its entire network to support DSL.

Keep in mind that during the dialup era there were a lot of things different than today. Two most important factors are this:

– The Internet (and computers) were still very new. Most people had *no Internet or Internet-capable devices* before 1995 or so. Why upgrade the network with data services that would only be used by maybe 5% of customers?
– Dialup modems were slow. The phone lines only supported 56 kbits / second, but modems weren’t able to achieve 56k speeds until the late 1990’s. Who would buy DSL when a regular phone line sufficed?

Basically DSL appeared after the Internet became popular, dialup hit a speed wall due to the limits of the analog phone system, and the telcos had enough time to physically build new network facilities.