Good lord - I do not miss those T1 braggarts in chat during the 'early' days!

In the early 2000's, my dad started his medical practice in a clinic with a T1. After using 20 kbps dialup, going to his office and browsing the web was a pretty unreal experience. He couldn't stand to use our dial-up at home.

This video is basically my CCNA training course circa 2001, but 100x better presented than Cisco's computer training ever did. Great stuff

Man, I remember when I was a kid I dreamed of having a T1 line. And then I got a bit older and cox came out with 3mbps cable internet. I was blown away. Fastest internet on the street between all my friends, which means we abused the crap out of my pc downloading music on kazaa lol

FINALLY an explanation of T1 that actually makes sense! I don't know if I'm not looking in the right place, but I have never been able to find an explanation of stuff like this without an insane amount of jargon. I am also infuriated that no one else has made videos on vintage networking topics and equipment like this before, including something like the SPARCclassic. Keep making more amazing videos like this!

I LOVE these videos on old networking. Please never stop making them

I worked at a local dial-up ISP in the late 90s. When I first started they had a pair of T1s, but later replaced them with a >1gbps optical connection when the closet full of haphazardly-stacked modems got swapped out for banks of 56k modems built on special cards connected through a common backplane. Having access to a low-latency 10mbps connection (limited by the computer's network card) was truly incredible.

I loved using a T1 line in college, would always download lots of stuff in the computer lab and burn it in a CD-R to take home which still used dial up. This was back when Napster was popular.

A lot of this was my life at Qwest at one time- finding spare pairs to provision a T1 (or anything lower like a 56K or ISDN etc), calculating the losses and if it would require repeaters and how much the job would cost, then working with the crews to solve roadblocks ("you can't put a pedestal there" "turns out the pair is too noisy"). Also, It's astounding how expensive an OC-12 or 24 cost at the time, yet I now have an equivalent fiber line for less than $100/mo

Honestly, hats off to your ISP for letting you demonstrate a real T1 line and BGP. This is an amazing series!

I used to dream of having a T1 when I was younger. Thx for the videos.

I feel fortunate, when I was a kid, my dad was in upper management at a major ISP. He worked remotely, and through his job, we had a T1 directly to our house.

When I was in the Navy (late 2010s), I actually was the one who finally decommissioned an AdTran we used for our old VTC setup. I always got a kick out of dialing up VTCs using it.

It's mind-blowing how far we've come in terms of connectivity in the past 20-odd years. Just to think that a lot of people have watches on their wrists that have faster connections to the Internet than entire corporations had back then. When I was working in the ISP biz in the '90s-'00s, we eventually got an E1 (European equivalent of a T1, but 2.048Mbps), and man, that was quick at the time - I used to stay late at the office to get all my downloading done 😄

As an operator of a startup ISP, this video was absolutely packed with information. Absolutely love it. Despite dealing with fiber and Gigabit speeds, almost the same jargon are still in use today, and I finally, FINALLY, understand where it all came from omg

I've been trying to forget all the T1, Frac, Frame Relay, etc circuits that I had to set up back in the 90s and early 00's. The setup was simple, but dealing with the different Telco tech's was often a nightmare (because they NEVER made mistakes, even after you showed them they did). Cisco 25xx routers were bulletproof, still are if you can tolerate the 10Mb speeds.

This is a killer series, thank you for taking the initiative to do this. You are doing God's work letting us young hacker's learn about good old days the grey beards talk about.

That's really cool your ISP let you do that. Honestly, I wish more businesses were open to such things. I get work is busy and you don't have resources to answer every single question or help every single person. Still cool to help out with something like this that can help people better understand the technology.

Ooo I spy me a Cyclades box there at the end! I used those back at my first ISP tech job in the 90s. So many great networking fundamentals learned back then. I truly love this series. Thank you dearly for putting this together.

Woah - I did almost exactly this work back in 2003 with a small moving and storage company as the IT guy. Excellent video to know is what is coming 80% of the time. The other 20% was an amazing "OH! That's what that was!". Excellent video and looking forward to more in the series. I love your take on preservation and restoration.

frame relay and fractional T1 might be interesting sidenotes. I worked at a large region ISP in the late 90s and while main upstream were multiple T3s, we had remote branch dial-in servers connected through frame relay. In the early 2000s my subsequent employer went from frame relay with channelized fractional T1 for voice lines to combined voice and data over T1 to VoIP over T1, and finally to cable. I personally was responsible for configuring the xylogics microannex XL in college for dial-in access (replacing a cisco STS-10) which led to my job at the ISP primarily maintaining banks of telebit netblazers with racks of microcom(?) modems. there was some talk of replacing the modems with newer netblazers that could take in channelized T1s and handle 56k "modems" completely with DSP on each of the DS0s, but after I left the management decided to replace the netblazers with livingston portmasters which stupidly only supported 30 ports instead of the netblazer's 32, requiring redoing the wiring. interesting times.

Our T1 contract in 2006 was 300 a month. Somewhere in the pit is my copy of O'Reilly's t carrier the definite guide

I remember kids in school (early high school) talking about getting these ... it was crazy and the speeds were crazy compared to what we were used to. I remember kids saying they wanted t1 t2 and t3 lines for their houses but were crazy expensive.... getting geeked out over a t1 at school brings back memories... those were the days...

I used to set up the CSU/DSUs and routers at the ends of T1s. I'm glad we no longer have v.35 connectors.

In the late 90's I knew someone who had a business server with three T1 lines, and I said where I worked we had a T3 line. He said it was the same speed, and I said 'Not even close."

The k12 school I worked at had a T1 for many years and we eventually started to saturate that T1 link. At that point we ended up getting another T1 and bonded it with the existing T1 which helped for a while. At the time we really didn't have much choice for high speed internet. We ran the Cisco 2501 and had a Cisco 6509 Core and ran Cisco edge switches. I still remember when we updated the fiber between the four campuses from a single shared 100Mb link to four dedicated 1 Gig links (I think that was 2007).

Great work, retro networking has been a bit underrated. A couple years back I set up an E1 in my lab using two Cisco 2500 series and network termination equipment, mostly out of curiosity for 90s networking and because the kit was available cheaply on eBay. I did the same with ISDN BRI, and have a couple of ISDN BRI and PRI test phones too. Fun stuff to play with and as you say, absolute game-changers back in the day.

You should also need to talk of the BRA ( Basic Rate Access ) since it was also part of the ISDN suite with the T1/E1 and provided up to 144Kbits/s ( with tricks and the correct hardware + subscription ) when the norm was 56Kbauds... Also, since T1 is American Specific, in Europe it's called E1 and it's a 2048Kbits/sec link ( 32*64K [with up to 30 usable for data] ) Edit : Oh and in lots of place in Europe, we used V.36, or X.21/V.11... V.35 was usually seen as a PITA due to the two different pin sizes that could be on the connectors and the indecent size of said connectors ( V.36 and V.11 use Sub-D sized connectors [ 15 pins for V.11, 37 pins for V.36 ]

I wish there was something stronger than a “thumbs up” because this video was stellar. A trip down memory lane, this was. By the time my old company retired T1s, we had four coming in for a 6mb connection which got split out by ISP equipment (AdTran not Cisco this time) to a PRI for voice, a half dozen or so analog lines, and of course ethernet. It went through our firewall, then hit the core router where we had at least five point to point T1 circuits, a couple were bonded and went to a single location. It was a great solution because we were able to push all the Internet and voice services out from a central location and save a ton of money. Indeed, like you mentioned, we in IT felt like gangsters at the HQ because we had faster Internet than everywhere else.

This reminded me of my setting up of ISDN in 1997, which I used until 2003. I had two 64 Kbps B channels, allowing 128 Kbps. I had this connected to a "Smoothwall" router and a network switch to both my computer and my brother's computer. ISDN was my only better option than dial-up; DSL was not available in my area.

Already one of the best retrocomputing channels.

Good times!! I worked for the PacBell (phone co) from 91 to 23. Learned all this stuff, working on a comm tech. The technology ride was awesome! Watched DS0, to .x25 to channelized T1, to full T1, to T3, and even Muxing T1 (called the T2 (rare)). I got front row seats to watch fiber come into our buildings.. grow and take over like no one EVER expected! Then watched, 1Gb, 10Gb, 100Gb, WDWM, and right before I left, 400Gb lines to customers... I really would love to come back into a At&t building 20 years from now and marvel!!

In 1996 I was a Software Dev Manager for Dialogic Corp.,, the then leader in voicemail and voice response systems for business. I needed surgery and had to work at home for a couple of months so they installed “fractional T1”, two bonded 56K lines. That gave me 112Kb/s of 24/7 Internet connectivity. Compared to the 56K modems in use at the time that usually connected at 33.6K, it was heaven on earth. Thanks for the memories!

Wow, that brings back memories. I was an ISP network admin back in '96 and managed all that equipment - the AdTran, Cisco 2500, plus a Radius server for a bank of dialups. We had a fractional T1 at first. but it still beat out any modem connection.

Can't wait to see more adventures of the ISP. Haha. Doing gods work here, bringing retro tech to people like me, who was born way after this.

This brings back memories. When an ISP in my country started offering T1 internet services, i went to them and asked if i could have it for my home. Truth being told, i didn't knew what T1 was at that time...in the mid 90s, to me it was just an internet link. The engineers with whom i talked, asked how many apartments in my building will be connected with T1. I was like why, i just want it for myself. They smiled and told me it would have cost $1000/month to bring T1 in your building. In the end, i got a dial up with that sweet sweet tone to listen to. And i used it only to chat via IRC...nothing else.

Watching this was a blast as it brought up so many wonderful mamories of my time at Florida Internet back in 1996. We had 4 T1 lines each from different providers, Adtran csu/dsu's, tons of punch down blocks for dial-in lines, racks of Portmaster 2's along with external modems with the cases removed and a custom bracket to make it rack mountable, Cisco 2501, and our servers (BSD/OS (using Pentium Pro cpus) and Solaris 2.5.1). I even certified in that version of Solaris at the time. Every piece of this was just loads of happy memories and I can't wait to see the next part to add dial-up capabilities.

Did sooooo much work on this sort of gear back then. Also taught the various protocols and troubleshooting them. Have Sage (T1 test set), will travel! Lol. You knew you were having fun when you got a grumpy call from MCI to stop crashing their DMS central office switch by whistling into a giant conference bridge (we were the manufacturer), which was setting the second most significant bit across 240 DS0s simultaneously - the “robbed bit” way of saying “yellow alarm” to the equipment at the other end of a T1… and causing the entire T1 circuit to flush down all phone calls on all 24 DS0s and reset the T1 circuit. One of the major benefits of ESF was this couldn’t happen - the alarm bits were moved out of the DS0s. Good times. Physical / hard loopbacks were stellar for end to end circuit tests. “Fake” software loopbacks couldn’t always be trusted. Numerous early CSU/DSU boxes had horrendous firmware bugs. And carriers had lord only knows how many devices along a path misconfigured to respond to in-band loop up commands, so you never really knew where you were testing to. If you really want a mind bender… think about this. A T1 circuit was synchronous. As copper coax and later fiber came on the scene, multiplexing a DS1 into a DS3 was common. And a DS3 was asynchronous - but still needed a master clock source. Wrapping your brain around that, is pure entertainment. I “remotely troubleshot” a T1 issue where the circuit wouldn’t come up and some very grumpy military brass were quite antsy. Something about a rather well known missile test range. After looking over a diagram that was faxed to us - we were the DS3 and DS1 equipment manufacturer - that looked like it was drawn in sharpie… my brain said “check that there’s one click source set somewhere on this stupid path. Asked em… heard someone in the background yell “it’s up!”, got thanked, and apparently some nifty middle test wasn’t cancelled that day. Haha. Fun to watch you guys building all this old old stuff on a tiny scale. I dealt with hundreds of DS3s and thousands of DS1s. Cheers.

I started with a company in 2014 with about 40 laptops all served by a single T1 connection... That was hell.

Wow that was well done. Insane to have a proper BGP route published by a 2500 series. It could barely fit a fraction of all current routes in its memory.

That brings back memories of working at a school district. Each building had a T1 line - the speed was amazing back in the day. Especially when school was closed - we (the IT team) would come in and surf using the T1's since nobody was on them.

Love this video! I worked for Cisco in 1995 and getting businesses online meant either ISDN(64k or 128k), fractional T1/T1, and frame relay. I helped many customers with either buying or setting up their Cisco 2501's, and worked with all of the technologies including that adtran unit, you mention in the video. I haven't heard these terms in years but would have to educate customers daily on proper setup, correct configurations, troubleshooting, etc. Loved this stuff!!

I remember working a for a local ISP in '97. We had a T1 line for 25 modems in our community. I loved walking into the office and having direct access to that connection. It was a warez's wetdream in those days.

What a fun series! I was an escalation engineer at Lucent. I spent countless hours walking people through configuring those Adtrans. Ah, the good ‘ol days.

I was the telecom tech for a large hospital group and we had T1 before the telco's offered it. It was implemented using microwave between two hospitals on opposite sides of town. It was used for data and telecom. Eventually the telco was able to offer T1 so we used them until other companies provided better/cheaper service via fiber. I think we had 72 T1's by the time I retired. Many of them were configured as ISDN with 23 bearer and 1 data channel per span for voice. I still have a couple of ADIT channel banks that I use for my antique telephone connections with an Asterisk box.

Man these type of videos make me feel old. I've setup T1s and T3s. I guess that is why I've been doing this for 30 years.

Great video! One note on the smartjack you have: it converts HDSL2 on the telco side into a T1 signal on the customer side. HDSL2 is a method of transmitting a T1 over a single copper pair rather than two. It also allows for a longer distance between repeaters, 9,000 feet vs 6,000 feet with a regular T1. The HDSL2 standard was published in 2000. The previous generation of HDSL came out in 1994 and had similar advantages, but used two pairs. HDSL1 allows for a distance of 12,000 feet between repeaters.

This brings back memories of the days when everyone and their dog would set up a dialup ISP in their house.

Just wanted to express how impressed I am with this video and the lengths you went to for proper testing. You stated that you wanted this series to be a sort of archive for internet history and youre doing a really good job. Really well edited and engaging video on a subject that is far too often documented in a mundane boring way. I wasnt alive for this era of routing, but retro computing and networking has always been an interesting subject for me. I learned bits and pieces of this when I was in college for my degree in networking and this was much more informative than any lecture i had. Wishing you nothing but success on your channel.

Awesome video. Surfing DALnet and the other popular IRC servers in the mid to late 90s, you'd always hear about T1 from secondhand sources but obviously 99% of people didn't have access to the technology. You hit the nail on the head, T1 definitely had mythical status.

Having lived this era, I don't want to return :). Great videos!

Ah the T1... In the late 90's I had 2 friends that were the only techs for a local ISP. They would invite me up on weekend nights to join them gaming on the ISPs connection, as long as I brought the beer. Was so sweet playing Quake from there when your opponents were all on 33.6 modems..... actually it was more of a turkey shoot. >=)

Love this, I've worked in VoIP for 15 years and we still use this technology to this day for voice circuits (PRI).

I started working at an ISP in the late 90s and immediately fell in love with the idea of having a T1. And now I write this from a 1 gigabit fiber line.

A fond memory I have of the early 90s BBS days was upgrading from my 14.4 to a Supra 28.8 pre- standardization. Supra told me I was going to be the "first" in Texas to have one (never believed it, but they did a good job making me feel special). I still get thrilled when I see those old aluminum Supra cases, though. What a fun time to in the game, connecting people via fido and wwivnet and every kind of sharing that brought me a couple of life-long friends.

Just stumbled about this cool vid! I am in the ISP business here in Germany and we used E1 Lines in framed (30 channels at 64000kbit) oder unframed (2048kbit/s) configuration. I still have 2 Cisco 2501 with Rj45 and BNC AUI Transceivers. Additionally 3 Cisco 2621XM and WIC-2T Cards. Use the stuff to show the beginning of the modern Internet to our apprentices. None of them were born when the 2500 Series went out of service. Now I feel old again.

That Adtran front panel brings back memories. We had a dedicated "point-to-point" T1 connecting two offices, and I thought those voice/data maps were just the coolest thing. During the day, you might dedicate 8 or 10 channels to voice, making it possible to dial-by-extension four states away, just the same way you called someone in the next cube. In the 1990's, avoiding long distance tolls was not an insignificant thing, though at the price of a P2P T1 you better be making a lot of inter-office calls. Then at night, you might switch the map to dedicate all 24 channels for data to transfer backups.

Reminds me of how we phone trunked PBX's... the good old days. GREAT video.

This is great. My dad had a T1 when I was in highschool around 2000 and it was the equivalent feeling of the early adopters of Google Fiber.

Old networking is the best. I remember having access to a T1 in the early 2000's. Now I've got 5 gig symmetrical fiber at home. What a time to be alive.

And then I'm sitting here, watching this video on this cutting edge 1.5Mbps... on my brand new gigabit install :D

This was a fun time to be alive.

This is awesome! I always wondered, back in the day, how things looked behind the scenes. Sitting here now typing this on gig fiber to my home that I pay $70 for. Was paying the equivalent (in 2023 dollars) of almost $200 a month for unlimited 56k access back in the day. Incredible changes in such a short time.

Many memories .... I remember that I setup an ISP using cyclades PR4000. Was THE BEST and FASTEST ISP that time .. good times. ❤❤

One of the benefits of working for some of those Tier 1 ISPs in the 90s (such as Digex) was a subsidized T1 to your house. I miss that. :)

I love how you're getting more and more interviews with these guys. I also really enjoy your visual design, the chroma-keyed backgrounds on hover-items so your background shows through, including doing it on video like your terminal emulator, gives it all such a cohesive aesthetic. But it's not overly gaudy or flashy like many other channels' attempts at similar aesthetics (various sci-fi lore channels come to mind). By the way, were you really going to pay whatever AT&T were going to ask, if they were even still offering T1s nowadays? I get that with cable and fibre they might've been lower than $2000 a month, but I imagine it still would've been $200-500 at least. Hmm, I wonder if anyone's compiled a list of T1 pricing over the years until they finally stopped offering it.

fantastic technology from outer space

In the Netherlands we call it ISDN, it is dail up... and paid by minute. You can combine multiple lines

I'm a networking student at the moment. Great to see Cisco IOS haha.

Holy crap, how have i nit found this channel?!!?!?? New sub here now!!!! Awesome content!!!!

Oh man, that Portmaster 2e quick shot at the end of this video brings back so many many memories! :)

I think I learned networking on that same model of Cisco router in highschool in the mid 2000's. We used the same gigantic serial cables to connect routers in pairs, each student was assigned one router. We had asked the teacher why we were using such gigantic cables but he never explained anything about them.

Man I've always wondered how this stuff after the DEMARC looked and worked in practice - this video greatly helped me towards cracking one of life's mysteries @11:20 *thank you* #ISPhealing

That "transceiver card" is called a "Smartjack". In the olden days, it was the interface for the telco to test the line, and tell if the CPE was even connected. For over 20 years, that card has actually be a converter - 2-wire HDSL on the telco side, and 4-wire T1 on the cpe side. That's what you appear to be hanging on the wall. (note the 2 fuses on the right [net] and 4 on the left [user]) There's a complete little computer in there, accessible from that DB9 serial port.

My High School got wired up with a T1 line in the year 2001 and the senior classrooms has access to Ethernet at every desk. It was incredible.

Watching this over 1Gbps home fiber, remembering 20 years ago I had connected to the internet over DSL for the first time at speed of 1.5Mbps. It just satisfying.

Fascinating! An actual T1 demonstrated end-to-end… always wanted to see that. Looking forward to the next one!

This is awesome! Thanks for the video!

Absolutely top quality video. Great job! This video must have taken a lot of work. Fun to watch, and I relearned a bunch of stuff. Can't wait for the next episode!

This is really taking me back and I can pretty much play along at home. I was involved with a computer group in the late 90's in Melbourne Aus, who provided ISP access to the members. We used a AS2511RJ as the access server with 16 external 33.6k modems connected to it. (I still have the router and use it sometimes as a terminal server at home). This connected to a 1003 (I think) ISDN router with dual 64k BRI interfaces to the upstream provider. We didn't use a Sparc as a server but old MACs running custom software. (I personally own a SS10 that could be used). I also have a Cobalt Raq2 that the power supply died on in a thunderstorm and have jerry-rigged an external power supply to it that has an interesting past. In the early 2000's the Aus government changed laws relating to hosting of adult material. The site operators just moved their hosting off-shore instead of having to comply with the new rules and abandoned the equipment in a server room. This equipment just become available for staff to take and I ended up with it trough a friend.

Wow! This is my home's current internet speed! Can't believe my family gets such new cutting edge tech as this!

I wish i knew all this stuff back then! Thanks for the trip down memory lane

Well done. 30 years ago I was selling 56K DDS DSUs and T1 DSUs from AT&T Paradyne, Adtran, Codex, UDS, Racal, IBM, Kentrox and a few others. I remember these days well. Got onto the internet at 1200 bps via dial up modem in 1994. There were no web pages in that year, email and FTP were king.

OMG I haven't seen one of those ATI CentreCom adapters and AUI ports since the 90s! I completely forgot about them. ATI was right next door to our new office on 501 E Middlefield Rd. in Mountain View (between us and Nortel) and we'd run over with a PO whenever we needed something instead of having to order from Fry's. We had the 2nd T3 in Silicon Valley, the first belonged to HP. It was about $25k/month. That was the reason Jerry Yang brought his school project over (running on an SGI Challenge S) to plug into our datacenter in 1995. It sat under a folding work table at the end of a server cabinet row. It was one of Yahoo's first servers.

Wanted to thank you for these videos, just started studying networking and it has helped so much going back to basics and understanding how it worked back in the day.

Fun fact, that conversation that you had with the medical alert system was actually a pre-recorded voice. When she asked you how you were, you could have said anything and the reply would have been the same.

I've always wanted to build my own retro ISP as I was too young & inexperienced to work for one in the 90's, however I was facinated by how it all worked. So this series is very satisfying to watch & bringing back a lot of memories. Keep up the great work!

What an amazing series. Really happy I stumbled across your channel, such amazing content. Subbed!

Can't wait for the modem part! This is so lovely, thanks for the great work!

This siries is what i've been wanting for years! Keep up the awesome stuff!

That was a great video! Just to share with y'all, in Brazil we use Euro standards and an E1 channel provides 30 voice channels or 2Mbps data. Back in 1995, the telco delivered to the E1 customer a single pair to the CO/PoP, an HDSL modem with G.703 output (TX and RX through BNC connectors or twisted pairs) and, if needed, a G.703 to V.35 interface.

I had an ISDN-768k line at work and I did SOOOOO much "work" online with that connection. :D

I work just down the street from Adtran's HQ. Nice to see their old tech being used.

Hahah this brings back some memories. My friends and I used to fantasize about having our own T1 lines. Little did we know that one day T1 would be considered extremely slow. Recently I was even looking at a 10Gb connection,

I installed and maintained T1's for BellSouth from 2000 to 2006. They were king then. And expensive.

Speaking of the growth of the internet, I remember buying a book back in the early 90s that was a Yellow Pages of the Internet. For the Gen Z'ers, that was a physical book with a listing for every known business website at the time.

Takes me back to my CISCO Academy days.. subnetting in my head

Thanks for your channel content, I look forward to the next part in this series. Kind regards from New Zealand.

Ibwork at a 911 center. We still use T1 with Adtran TA1500 channel banks. We also ha e 100s of our own T1 running on a Sonet. We have been converting T1 to AT&T Ciena VPN it works well. We still have many T1 today. We run them over IP to TDM converters. Great video.

Five years later a kid barely out of highschool set up a 1000-device network on similar equipment, using similar commands, and sold the 4Mbps frame relay connection to data hungry Australian start-ups. What a walk through memory lane!