I remember seeing them a bit, but not knowing what they meant. I've found this which explains it a bit.

https://en.wikipedia.org/wiki/T-carrier

> The most common legacy of this system is the line rate speeds. "T1" now means any data circuit that runs at the original 1.544 Mbit/s line rate. Originally the T1 format carried 24 pulse-code modulated, time-division multiplexed speech signals each encoded in 64 kbit/s streams, leaving 8 kbit/s of framing information which facilitates the synchronization and demultiplexing at the receiver. The T2 and T3 circuit channels carry multiple T1 channels multiplexed, resulting in transmission rates of 6.312 and 44.736 Mbit/s, respectively. A T3 line comprises 28 T1 lines, each operating at total signaling rate of 1.544 Mbit/s. It is possible to get a fractional T3 line, meaning a T3 line with some of the 28 lines turned off, resulting in a slower transfer rate but typically at reduced cost.

The T1 users were like internet royalty to us dialup users back in the Napster days. I often pondered where they must be to get such an amazing connection (Universities, I assume). Now even in rural England I get a reliable connection that's over 50x faster. Even mobile is faster than that. How times change.

AHH, if only I lived in the countryside, rather than in a London suburb where my maximum ADSL speed has for at least the last decade been barely better than a T1 downstream, and hardly better than dialup upstream!

I'm stuck in Putney grrrr.

Unfortunately in the parts of the rural US where my employer frequently operates we still have difficulty getting a connection on par with a T1.

I remember being on dial-up as a kid back then and being insanely jealous that kids in college got T1 connections in their dorms. One of the reasons why I wanted to go to college as a kid was the blazing fast internet speed. Downloads that took hours for me, took seconds for them. It sounded like heaven to me back then.

I went to a state school that hadn't completed networking their dorms. Even at school, I had to use dial-up to get my email (using Pine through a VMS). My girlfriend at a different school had high-speed access in the dorms.

I remember making the 2 hour trip to visit her, and half of my excitement was all the music I could download once I got there.

I show up, and find out she hadn't connected her computer yet! First priority of that day was going to the campus bookstore to buy an ISA network card and 10Base2 terminators and connectors.

I learned what T1, T2, T3, OC-3, OC-12, and OC-48 meant back when counter-strike servers were adding it to their server names. However now that I think about it, most of the OC-3+ servers were straight up lying through their teeth. Still got me to join though.

OC-3/STM-1 155.52 Mb/s can carry 63 T1s OC-12/STM-4 622.04 Mb/s OC-48/STM-16 2488.16 Mb/s

     OC-3/STM-1   155.52 Mb/s can carry 63 T1s 
    OC-12/STM-4   622.04 Mb/s
    OC-48/STM-16 2488.16 Mb/s

I think that's 63 E1s. An OC-3 can carry 84 T1s (3 x 28)

d'oh. you are correct, sir.

Back in 1995 my friend and I ordered a T1 with the intention of starting up a web hosting company. The startup didn't work, but we did end up with blazingly fast (for the time) internet access. I still remember downloading the first version of Netscape and it took just a few seconds. I almost fell out of my chair!

Long story short, things must have been so crazy and disorganized at the vendor (I guess) that even though we never paid a single invoice for the T1, they took over a year to shut us off.

> I still remember downloading the first version of Netscape and it took just a few seconds. I almost fell out of my chair!

This is still how I feel everytime I download a large file in seconds. I guess I spent so long accessing the internet over dialup this rapid (and relatively recent) explosion of speed at the edges is truly impressive. It's a little ironic that our most popular protocols and services these days reject p2p so thoroughly.

Wikipedia is your friend: https://en.m.wikipedia.org/wiki/T-carrier

Take a look at ISDN, too. Family friend had that in their home.

'Only' 64k and 128k speeds. However, it was 'always on' compared to dialup over POTS lines. 4-5x faster for uploads and 2-4 times faster for downloads, so most dial-up users would have coveted it.

and the monthly cost kept it out of greater adoption.

I believe it was also used for high fidelity, low latency audio for interviews and music production.

Don't forget video games.

In a game with good network code such as Quake 2 / 3, you could expect at best a 150ms ping time with a 56k modem in ideal scenarios but on ISDN you could get half that which made a world of a difference.

I never had ISDN but I knew a few people with it. It was like you were playing a completely different game. Then cable came and it blew everything away with getting 20-30ms ping times even in the early 2000s.

Ah, I was only playing original Quake with a direct dial-up to a friend’s modem, for 1-on-1, but we did have it working in the computer lab on 10-baseT.

If somebody went to turn their desktop slightly, the coax would pop out of the t-connector and those further down the chain would be at a severe disadvantage.