What Was ISDN?

I launched RustNet in 1992 as "the first ISDN ISP in Michigan." We offered a blindingly fast internet speed of 125k! At the time Silicon Graphics had added an ISDN port to its latest workstation, which I had for the engineering design work we did. The launch of our ISP occurred at an industrial expo at Cobo Hall in Detroit. We were not set up yet so I talked to the product manager of the ISDN feature at SGI and he was kind enough to let me dial into his desktop workstation in his office. All I needed was to get Ameritech to drop an ISDN line into Cobo Hall. One trick we learned: if a regular dial-up customer complained about speeds we would call Ameritech to schedule that customer for ISDN. The phone company would remove something from the line (filter? impedance?) to prepare it for ISDN. Then we would cancel the order and the customer would get the full 56k from their modem.

Back then we had four primary rate connections 2.048MBit/s each (30 ISDN B channel) to transmit data to several subsidiaries. This was quite a lot of bandwidth at the time. Our litte on demand network started at 02:00 in the night when tariff was lower (paid by connection time, not by volume :D) and used Ascend and Cisco routers Ascend was always much quicker setting up MPPP channel and therefor preferred, but Ciscos where a bit better utilizing larger 30 channel MPPP connections (and some destinations preferred Cisco)

It was quite 'fun', because starting with morning when tariff changed everything had to be transmitted and if something didn't work out right (to slow buildup of the MPPP channel, delay in the batch jobs delivering the data) someone had to monitor the process in the next night to prevent further backlog. For a long time there was only a 64kBit (later 128kBit) connection over the day regular connectivity.

Eight MBit carefully distributed over 120 channel. With all the support equipment a server rack, filled by 2/3. Ridiculously little today, even over air. It sounds as if one talks about the ancient Egyptians, but it is only 25 ago

ISDN did have multiple channels, in Germany you would get two data channels (B1 and B2-channel, 64 kB/s), and the line has a D-channel (something like 4kB/s) for network purposes. First you could bundle the B-channels to get twice the speed, at twice the price and the land line was busy if one did that. That feature got me into trouble with my parents quite regularly.

Second someone figured out that the D-channel can also be used to send data to arbitrary endpoints in the phone networks and dropped a messenger app on a Friday afternoon in '98 or thereabout. That was a pretty fun weekend, unfortunately the hack had stopped working when I came back from school on Monday.

The article addresses the big miscalculation by the telecoms, as I see it, though somewhat obliquely.

In the telecom world, the telecom was the network. If you wanted to exchange data with someone, you placed a call to someone directly. Everything was envisioned as some form of point to point session between subscribers. Whatever it was, it was one subscriber contacting another. The telecoms didn’t really conceive of what would become the Internet as we think of it now. As far as they were concerned, the Internet didn’t provide anything the telecoms couldn’t offer—and bill for.

They were caught flat footed when customers started dialing up ISPs and cutting the telecoms out of the loop. If you wanted Internet, you got ISDN, but you used it to call an ISP that was not the phone company.

Not that the telecoms weren’t visionary — they largely foresaw everything we do today. They just assumed they would continue to be the sole provider of those services. They built a network with that in mind.

And then we all went and built our own network on top of that.

They scrambled to try to charge us for using our voice lines for data, and then they managed to slide DSL onto the rate card, and ultimately became actual ISPs.

But that wasn’t the future ISDN was built for. It wasn’t built for a world where an ISP was even a thing. It was built for a world where everything we now do on The Internet would show up as a line item on a bill from AT&T.

Got ISDN as a previous job as parttime helpdesk employee at an ISP. Together with the rise of numberous dail-up providers, including the legendary Superweb. It would allow free internet against a fix rate, not paying per minute, which was something new for the Netherlands. It would only allow one or two hours after it would disconnect you and you had to redial. Due their succes getting dialed in again could take quite long (too many users, not enough lines). So I wrote code/script and made changes to the Linux distribution to allow me to dial with my second line as part of my ISDN, starting ten minutes before I would get disconnected, and “transfer” the connection to the new connection when it was finally able to dial-in, hence having internet 24hours a day. Good times! Superweb didn’t exist very long…

Before ADSL was available and affordable, I did have ISDN at my place. It was charged by the minute, so I could not leave the data always on. I set up an always on Linux box at my apartment with a PCI ISDN adapter. A voice mail application answered calls on one of the 4 ISDN phone numbers.

I modified this voice mail application to accept a PIN code to open PPP on the other B-channel to the ISP and read back the dynamic assigned IP on the phone. This was something I could not do with a single analog phone line and a modem.

This was not the reason to get the ISDN, but this was the first time I could remotely access my systems at home at will. Not that I needed to that much, but I could.

Back around 1996 I was working for a non-profit rural digital project in Devon, Southwest England, called Project COSMIC. If I recall correctly there were 2 main types of ISDN in the UK at that time (a) on-demand, which was similar to dial-up, and needed an ISDN modem, or (b) leased line ISDN which was always on 24x7 and terminated in a Router. I was lucky enough at COSMIC to have access to a 64 Kbit/s ISDN leased line. As I recall it was insanely expensive, I think it was about £16,000 / year in 1996, and that doesn't include the initial install cost where they had to drag a cable across the fields and install poles.

On the end of COSMIC's leased line, after the Bay Area Networks router, we had a simple Ethernet Hub, a Windows NT 4.0 Server, and several Windows 95 desktops. We used IIS to serve websites and email for customers from the NT server, and all the machines had public IP addresses without a firewall - the Internet was a different place back then!

A few years later ~1999 they upgraded to a 128 Kbit/s ISDN leased line, I think costs had decreased and the additional capacity did not cause a large jump in price. It was brilliant! Many games of Quake were hosted ;-)

Later in around 2004 I worked for a company that had a leased line, but they used an entirely different technology - LES10 (10 Mbit/s) - but it had a range limitation and so you had to be within perhaps 10 KM of your ISP.

Of course, just before that, around 2000/2001 some parts of the UK started to get ADSL trial role-outs. I was lucky enough to be at University in one of the first areas (Derby), and we were able to get a 1 Mbit/s connection for about £50 / month which we shared between 5 of us in our student house. After that I didn't see ISDN around much, and LES10 was a pretty niche use-case anyway.

Today I am happily sat on the end of a 100 Mbit/s consumer microwave connection for about €30 / month.

I had ISDN in South Africa for a while back in the day.

Aside from the higher throughput, one of the other great things about it compared to analogue dial-up modems was the almost instant connection speed while old analogue took tens of seconds, maybe even a minute.

But the biggest thing that really made it feel “responsive” was its digital nature, meaning that your baseline latency was mere sub-10 milliseconds instead of 150ms for analogue.

Generally our monopoly telco was despised, but they had a great offer called “R7 weekend” where from 7PM Friday to 7AM Monday, no matter how long the (domestic, possibly local, only of course) call you would never be charged more than R7 for it. This meant that you could be connected for the whole weekend at 128kbps for R14 (~1.4 USD) at the time (2003-ish).

My main exposure to ISDN in Australia was in radio stations.

In Australia, we had an ISDN2 product (BRI) which gave us that 128Kbps bitstream. Hardware boxes from brands like Musicam Prima, Tieline and Comrex would allow transmitting a bi-directional MPEG2 audio stream. When I used to dial these things, you’d hear a low-bitrate stream first for a few seconds before the 2nd number would dial and you’d get that full 128Kbps. Different brands of codecs were theoretically interoperable, subject to the settings and codecs matching. I remember the Tieline codecs probably sounded best because they had their ‘MusicPlus’ codec (which I think was actually AAC+ under the hood). But most other codecs were only MPEG2, so you were stuck with that.

We used to use these for outside broadcasts, backup links between the studios and transmitter site, and links to other broadcasters (e.g. the TV news presenter dialing in to tease the nightly news headlines).

Even after the internet was well and truly established, ISDN was still used a lot for this because it was ‘standardised’ and also a pretty much guaranteed bitrate - whereas ADSL might give you a couple of megabits but with no guarantee you’d have that between your two locations at all times. When you need low latency two way conversations, you can’t just dial up the latency and keep re-transmitting packets until they arrive.

The local telco used to be able to install these fairly easily on a temporary basis so you could do a broadcast from a temporary location (e.g. local advertiser books a broadcast at their store). You couldn’t really get a temporary internet connection put in at the time. You could get stereo audio both directions, but often you’d use the left channel for your program audio, and the right channel for an intercom in everyone’s earpieces. So long as you played the music from the studios and just fed the mics down the ISDN from the remote location, the quality was passable.

We also had ISDN10/20/30 (PRI) for general telephony. I interfaced these to SIP PABX’s a few times with Patton boxes, but the docs were always for T1 not our E1.

I don’t really miss it, but it’s kinda cool in retrospect.

On the ISP side, ISDN was a crucial part of scaling out dial-up ISPs. CLECs (Bay Baby Bells) would route calls from geographically large calling areas --- all of Chicago, say --- to a single colo cage on an ISDN PRI. Access concentrators (then called "terminal servers" --- Portmasters, Ascend routers, Cisco AS5x00s) would take 56k modem calls on individual PRI channels.

Here in Australia, ISDN Data over Voice (DoV) was in fairly common use. Telstra (the major telecom here particularly in those days) charged an untimed flat "local call" rate (a few tens of cents) for an ISDN voice call, and by the minute for an ISDN data call. It didn't take many minutes for a voice call to be vastly cheaper.

At a technical level both types of call are a 64kbps data connection, with just a flag to discriminate between the two. All the major suppliers (Cisco, Nortel, ...) had software options for their ISDN gateways to tell them to set the voice flag when making an outgoing data connection, and to treat voice calls as data calls when they were received.

This was extremely common and Telstra never seemed to do anything about it. Just a funny memory that this article brought to mind.

I remember visiting relatives in Switzerland in the 90s and it was the first time I’d seen ISDN - felt like they were living in the future while we were still on dialup in the US. I was thinking earlier today how when I was that age how amazing it would be to have fiber someday - has taken 25 years but I finally have it at home, and it still isn’t fast or reliable enough

Serbia (former Yugoslavia) was mostly in turmoil in the 90s, and while I did get online using dial-up in 1995, new tech was (very) slow to arrive: I used ISDN for a few short years in early 2000s before ADSL finally arrived. It was amazingly reliable even in Serbia.

But compared to the regular 20V phone line, ISDN used something like 120V (which I learned by carelessly changing the connector like I used to on the regular phones), and in a country where power went out regularly, I wondered how much power could I get out of it for emergency situations.

in the mid-90s it was often the only option for >14.4kbps internet in residential areas. unfortunately the tariffs charged by the minute for voice and data calls so it was prohibitively expensive (at least for our household).

the hack (in the US) was that ISDN was often offered as part of "centrex" service which was a sort of phone company managed PBX-as-a-service offering. so rather than businesses setting up their own local mini telephone switch (a PBX) that they'd hang all their extension phones off of, they'd just get ISDN phones and connect directly to the phone company and have the phone company manage it all. the trick was that "intercom" calls within a centrex were unmetered (think intra-office calling), so an approach to building an ISP would have been to sign up for centrex service and then install a branch phone on that centrex at each customer site, then all calls into the ISP would be intercom calls and would be subject to unmetered tariff.

i used to drool over the idea of one day getting my hands on an ascend pipeline 50 and its sweet, sweet 128kbps of bandwidth. then one day i finagled a visit to a local software company and met the founder who was struggling with getting one working (it was paired with one in his home, so he could make use of the company's t1). he jokingly offered that if i could get it working he'd offer me a job: 45 minutes later the link was up and few hours after that i was shaking hands with the head of engineering as they made good on the founder's word. fun times!

Many fond memories from using ISDN, but there was also some frustration. How far you were from the Central Office played a critical role on whether you could get ISDN and I was at the limit. Ended up switching equipment more than once trying to find the perfect device that could deal with whatever signal issues came from being around 15,000 wire feet from the CO.

Haven't seen much mentioned about it but as I recall ISDN was also symmetrical vs analog modems which had a small back channel. Equal upload speed made it easy to keep up with sites that enforced a sharing ratio.

ISDN also exposed the call setup information sort of like caller ID did on analog lines, but it came over the control channel instead of between ring one and ring two on a Plain Old Telephone Service (POTS) line. Some ISDN devices had call handling that was pretty sophisticated - a precursor to Asterix and like software/customer managed PBXs. The upshot was you could screen and reject calls prior to their tying up one of your channels. And if you did want to take a voice call, you could take one channel down and still have a 64k network connection going while your wife used the other to talk to her sister. Huge wife acceptance factor vs "Don't pick up the phone, I'm using the computer!"

It was a fantastic album - https://en.m.wikipedia.org/wiki/ISDN_(album)

The condo I'm living in (in Tokyo) was built 20 or so years ago and features a karaoke room for the residents. We recently got a notice about how they will have to do a full makeover of the karaoke system because the current one only works with ISDN and the vendor is phasing out support. IIRC the quote for the makeover was around $10k

In the late 90s, I lived in rural Appalachia and had terrible pings with lots of packet loss on my 56k modem. Found a local ISDN provider and my parents paid to have the ISDN line installed into my bedroom.

I was in heaven! Now I could play Action Quake 2 and Quake 3 Arena without glitching all the time! Those were good times :)

I love all the anecdotes here. The mid-90s were a time of the creation, explosive growth, and decline and fall of the Internet Service Provider industry. Like many other people here, apparently, it was a big part of my life. I worked at three nascent ISPs, the third of which I started with a friend from college, and it was where I learned a ton about networking, sysadmin (FreeBSD), software development, handling customers, etc., that turned out to be foundational to my career decades later.

And I did have ISDN at my house for a time. (Bonded, blazing 128k!) We used the Centrex trick that was mentioned elsewhere in the comments.

It Still Does Nothing.

Right at the start of the 2000s DayJob had ISDN (initially using one channel then the two bonded for 128kbit), and while it was night and day compared to the unreliable 42/21¹ I got at home from a nominally 56k connection², it wasn't all that impressive compared to what I was used to at university in terms of throughput most³ of the time.

Admittedly the office was well out of town making a "proper" leased line extortionately expensive, so ISDN was the best practical option until we moved.

----

[1] or 33k6 when I forced it to use that standard to get the faster upstream rate

[2] always on, fixed addresses, faster, didn't drop if a sparrow farted nearby, …

[3] the link we had there did get over-contended at times, but not as much as you might think as this was before connections were available on dorms so Pele had to head to a computer room to get online so if I did get lower than ISDN performance it was likely due to the other end or peering limitations between

At the end of the century, 1999, I had one of the first and also one of the last ISDN internet flatrates, offered here in Germany. It cost around 60 Deutsche Mark per month. Around year 2000 this ISDN flatrate became obsolete, because DSL was pushed into the market, also with a flatrate option. Now you could get 786kbit/s instead of 64kbit/s. :) I used my (and my only one) ISDN telephone to 2017 though. It lasted almost 20 years without any problems. Then we moved and now it is all VoIP.

For me it was the feeling of "being on the internet" that made ISDN so special. My computer had a fixed IP address, a name in DNS and the router at work had of course dial-out, so I could telnet into it from anywhere on the planet, authenticated with the same Kerberos tickets that got me in at work.

I remember connecting my laptop to ISDN public phones in Tokyo in the early 2000s to check my email when I was away from my office. Not a particularly fond memory, but it gave me an early taste of the always-connected world we live in now.

The phones apparently still exist [1] but the digital data function is being phased out [2].

[1] https://www.ntt-east.co.jp/en/ptd/contents/mag_public_digita...

[2] https://www.ntt-east.co.jp/ptd/contents/mag_public_digital.h...

I had ISDN back in 1996 and it was great. It felt dramatically faster than a 56k modem because ISDN has much lower latency. Web pages were so simple in those days they loaded almost instantly.

That brings back fond memories. In high school (a long time ago), I coded up a client-server application in Perl/Delphi to utilize the ISDN D-channel to transmit small amounts of data by repeatedly dialing a destination, using the call initiation metadata to communicate, and then hanging up before the call got established.

In Europe at that time, every call (even local ones) started getting billed as soon as the dialed party picked up. So effectively, this allowed for fee-less small applications that didn't need much data, but that I wanted to invoke many times a day (think checking email, checking server status, IM, etc).

ISDN absolutely was exhilarating “technology from the future” during the 90s and even into ~2000 era just before general cable/DSL proliferation.

It usually just worked consistently and at unbelievably high data rates vs theoretical “56k” even on 64kbit/s single channel. Meaning basically 2x IRL downloads vs 56k at usually tenable full hop bandwidth of constant 8kb/s.

I kept being mesmerized by “just the basics” of ISDN + TCP/IP; it all was working just so flawlessly. For years on end, and each time I went online. Pure wonder and amazement.

ISDN was a great upgrade for me in the 1990s, and once I found out how to couple two lines into one "massive" 128k, it was pretty mind blowing. Connecting to the Internet was also snappy (as opposed to dialup with the whole modem song) and could even be done on demand if you were brave.

Believe it was 1995 or '96. We had 20 remote sites connected with "128K" ISDN connections. There were a pair of PRIs at our main data center. Ascend PRI router (concentrator?) on one end, Ascend ISDN boxes at the remote site. (IRC, Ascend was formed by former Hayes modem engineers). Occasionally there would be issues bringing up a site and I would be invited (allowed?) into the Telco Central Office to troubleshoot. Standard ISDN troubleshooting tools were a laptop, a portable sniffer (Toshiba laptop with 96K of memory and Network General Ethernet adapter), a BERT tester and, occasionally an oscilloscope. For the more difficult sessions I would work with a remote Anixter engineer (before they were bought and screwed up by SBC) who was a veritable rocket scientist. We'd been running clean for a couple of years, and I was on vacation at Disney Florida with my wife and small children when I got the call that one of our supervisors had somehow managed to wipe the configs on the PRI boxes. I spent the next two hours on a bench under the Epcot ball walking one of our best desktop people through reconfiguring the boxes from memory. I do not miss ISDN, 56/64K, T-1, T-3, SONET. Currently running on privately owned fiber and never want to go back.

Obligatory reference — electronica legends the Future Sound of London (FSOL) [1] produced an album called "ISDN" that was originally broadcast over ISDN lines in 1994:

https://en.wikipedia.org/wiki/ISDN_(album)

It's an interesting relic of a specific cultural moment in time just before the Internet broke through. With ISDN, you could send a nearly hi-fi quality digital audio stream to anywhere in the world, but it wasn't yet on the open network that would define the actual future we now live in. Quite fitting for a band with "future" in their name.

- -

[1] Even if you don't know FSOL by name, you've most likely heard their massive 1991 club hit "Papua New Guinea" somewhere.

Was glad to see some facts about using ISDN for voice acting in there. When I was a teen, my interests were split between computers and theater. I was SHOCKED when I found out some of the actors I got to work with had ISDN, and not for internet!

Still use it, and there isn’t really a replacement at the price point or reliability. When all you need is a single voice circuit for a radio station to be able to contribute from the middle of nowhere, it fits the bill very well.

Obviously it’s going (how soon? Well we will see shortly if 2025 is kept to), and it will be a sad day. International isdn is pretty much dead, and has been for some years, but in the U.K. it is still reliable and functional.

| The problem with ISDN was simple: We already had effective options for everything it was trying to do

Man, can't disagree more. I didn't become aware of ISDN until I was using a 14.4k modem for a dialup internet connection, and the idea of having an always-on "digital" connection to the internet that was almost 10 times as fast as what I had was absolutely, unfathomably futuristic.

It seemed like the kind of thing they only had in Europe and Japan though. I was aware that some people in the US had it, but I had no idea how it was delivered or how one would go about getting it.

In the end, we were super late to getting DSL -- I think maybe 1999 or thereabouts, long after most neighborhoods near me had it. Going from 33.6k to 256kbps was the biggest "real" jump in internet speeds I've ever had, to this day.

By comparison, going to a shared LAN on a college campus, or a 10Mbps cable connection, to 25Mbps, to 100MBps, or whatever series of jumps got me to 250Mbps and beyond were barely noticeable from a user experience standpoint. Yes, files downloaded faster, but it didn't "feel" faster in normal interactive use.

Hell, I only got gigabit fiber "because I could" and the jump from 1 gig to 10 gig symmetric is almost laughable because it's impossible to use anywhere near that much speed on a day to day basis.

We used to use ISDN for our videoconference system (PictureTel –expen$ive), in the early 1990s.

We used one half of a line (64KB).

The quality was … less than ideal, and the latency was about two seconds.

We also used it for our corporate Internet connection.

I don’t miss it.

ISDN was a true gamechanger for me. Before that, we had a 56k modem and I couldn't go online without blocking my parents' phone connection. Also, with ISDN came our first internet flatrate.

I used ISDL, a related technology based on ISDN operating at the same bandwidth, for a few years in Colorado in the early 2000's. It was the only thing better than dialup at the time. The ISP was Megapath Networks. Still have the Efficient 5871 IDSL modem somewhere.

Always on, static IP address. It was easily the most reliable service I have ever used, then or since. The latency was astonishingly low as well. But 128Kbps wasn't adequate and I moved on when I could.

Man, the idea that ISDN was going to last 50 years has to be one of the bleakest Bellhead memes I think I've ever heard. "You will only have 144kbps and be happy."

"I Smell Dollars Now", based on how many consulting companies were selling ISDN advisory and educational training/presentations.

I've been using ISDN in Italy in the late 90's at home and it was great... Many didn't know its potential, but even the fact I could use a router that connected to both lines and automatically dropped one once a call was mad or coming, made my life way better...

And before ADSL become a thing, having a 128k symmetric digital connection with low ping was a dream!

A place I worked in the early 2000s had ISDN. They had two telephones and two channels for the internet. There was this sweet period around that time before broadband was ubiquitous where websites were still lean enough to load instantly on an ISDN connection. We've regressed a lot since then and now even Google doesn't load that quickly.

In Japan, they used to have ISDN phone booths (what is a “phone booth”?). These were grey phones. Never tried using one.

In my CCNA training in 2007ish we actually got to use an ISDN simulator of some sort. It was a large physical box. I think you can buy them on eBay still.

Pretty sure this is no longer on the CCNA unfortunately. Maybe just a small mention.

I find it much more amazing that T1 dates back to 1962. What could talk at 1.5mbps in 1962? Mainframes I guess?

Then there’s the fact that this speed remained fairly state or the art until DSL and then cable modems.

There was also T3 in the 1990s for a whopping 45mbps. I worked for a bit for an ISP in Cincinnati in college that had one of those running to a data center. That DC was full of racks of Windows NT machines with unused mice hanging off the back of each so they would boot properly.

Those days were both fun and awful. It was really a frontier feeling but the tech was clunky and connectivity was expensive.

It was also a terrific Future Sound of London album (that still sounds great!)

One really cool thing about ISDN was that it connected almost instantaneously (within a second). In fact I remember the first time I used it, I thought the connection had failed because I could not imagine it connected so fast. This allowed you to have the illusion of being always online by auto dialing just in time. I remember setting up modemd (IIRC) to keep the connection open for at least the minumum charge time of my telco provider. This was in NL some time in the 90s.

We networked our nerd house in the early/mid 90s, using an ISDN terminal to get that blazing fast 128kbps. Back then, people weren't constantly streaming video, so most of the time when you were downloading stuff (kernel source, Linux distros, funet.fi, sunsite.unc.edu, etc.) you got the whole 128k to yourself.

Most people at the phone company had no idea what ISDN was, so it took a while to find a technician there who could get up provisioned, etc.

I had an ISDN line in my home that, somehow, had a direct connection to the intranet of my employer at the time, Infoseek. Not sure how this was all arranged, but it was just like having a very long wire that went to my employer. Someone in Infoseek's IT department set it up.

Sometime after, DSL replaced this. And I used some form of DSL until, eventually, cable modems became cheap and fast and available in my area.

ISDN was somewhat mandatory in Germany for internet access during the 90th. Carriers pushed it very hard.

The combination of both channels was a unique selling position to leave modem speed in the dust. 64kbps could be combined to 128kbps simultaneous download speed - of course, it costs you twice as much. ;)

The downside later on was, that it took a long time till the next generation was available, in Germany it was DSL.

I have a conspiracy why it was so popular in Austria and Germany: ISDN had an official matching translation to German: Integriertes Sprach- und Datennetz

The love for ISDN was absurd. In Germany they even rolled out slower DSL services for a while to keep ISDN alive (ASDL-over-ISDN).

What was great about ISDN is that it started the trend of flat rates in some places. As you kept the modem connected 24/7 you could still do phone calls. I’m not sure we would have seen flat rates as quickly without it. Latency also was amazing compared to 56k. For online gaming it felt amazing.

//edit: one interesting memory I had was that upgrading from ISDN to DSL would wreck latency. Most ISPs thus gave you to option to disable interleaving to improve latency for online play.

ISDN was quite popular (albeit expensive) in the Netherlands. I remember enviously watching at a friends house how you could connect instantly without dialling up and how 64k was significantly faster than “56k”. Then we bundled the lines to get 128k and went onto Napster. Boom!

The real shame is that PSTN lines continued to be installed through decades, despite ISDN existence.

Thankfully, wrongs have finally been righted with FTTP/FTTH being widespread now.

I enjoyed ISDN internet access at 128kbps via high school in the mid 90s, and shitty v90 through early 2000s.

dual challenge ISDN was a reason I was trying to move into a Roseville Telephone (Northern California) area. at the time, it was awesome. web pages were like flipping pages in a book. the latency was nice and low for the time.

until cable & DSL came along, it was awesome.

I used ISDN internet for a few years in the 90s before DSL became available. It was a big improvement over normal dial-up because you could still use the phone while online. Or use two lines for 128kb downloads if you weren't expecting a phone call.

I have quite fond memories of working on ISDN video conferencing in the not so distant past. Video calls are quite possible on 64kbps (qcif, g728 and h264). Though it was also possible to use a whole PRI and make a call using 2Mbps.

I had an ADSL connection in France in the late 90s. It did not do bonding of the 2B channels so was limited to 64kbps, but the latency was much better than with a modem so it felt much snappier.

I had it between a 27k modem and ADSL. It was amazing, 64k and my family could still use the phone, and at night I could fly with nothing less than 128k. Great times!

Don’t forget Frame Relay, which was a good complement to ISDN.

It Still Does Nothing

I spent a long number of years frustrated by analog dialup as I read stories about ISDN being used in places that like Europe.

But for a brief time just before the turn of the century, it made sense to get ISDN at home (in the US).

I already had a free 24x7 dialup account from a local ISP that I'd done some work for (the free lifetime account was part of my pay for a job).

And the local phone company was circulating mailers for ISDN circuits -- installed for free, and with a very low monthly rate, and with unmetered local calls.

So I asked my ISP buddies if it'd be OK, and they said sure, but asked that I keep the channel count low unless I was really using it.

It worked great.

I was able to set up my (ZyXEL) all-in-one ISDN router to keep one B channel connected at all times, and to connect the second B channel only when average bandwidth utilization required it.

The ZyXEL box also had two POTS jacks for connecting telephones. One of them was used for the house landline, and the other was connected to an analog modem for BBS duties.

The circuit had two phone numbers assigned, and either POTS port could use either B channel.

It worked slick: Always-on, low-latency internet that got faster on demand (connecting the second channel and logging it in took only a fraction of a second), with a static IP and customized reverse DNS.

And the dedicated POTS jacks worked great: These provided the highest quality telephone calls I had ever heard.

Management was automatic: Inbound calls would drop a B channel automatically if that was needed, and so would placing an outbound call.

It all happened transparently, thanks to a combination of software at all ends (my end, the phone company end, and the ISP end) with MLPPP running the show in IP land.

A beautiful symphony of weird telephony tricks, all working in time to be useful and reliable.

And I do not know if it was common, but my particular circuit was provisioned so as to allow me to specify any number I wanted for caller ID purposes.

So on outbound calls, I could change my Caller ID to any number I wished.

I never used this function for personal gain, but I could, for instance, call up a friend's place and have their mom's phone number (and name, due to how CID works) show up on Caller ID.

"Hey, yo. I'm totally at your mom's house right now. What? No, it is like that. No, she's sleeping right now -- you know how it is."

"Except: Just kidding. I'm at home by myself as usual, and just fucking around with my ISDN line because I have no life. But that was a neat trick, wasn't it?"

ISDN was night and day. Had a 56k Zyxel before getting 64k ISDN. Speed wasn't much faster, but dialing was instant!

ISDN is what made my parents’ phone bill explode. 128kb/s with two channels was like a dream come true haha

Extremely overpriced in my area.

It was the solution to mothers screaming at you because you hogged the phoneline

I still have PCI and ISA Fritz ISDN cards somewhere, if anyone wants them.