We are definitely spoiled these days in terms of Internet access. In much of the world gigabit speeds are common and even cheap plans are likely to be measured in 100s of megabits. But there was a time not long ago when a fast modem received at 56 kilobits per second. If you couldn’t justify a dedicated T1 line and you had a lot of money, you might have thought about ISDN – the Integrated Services Digital Network. [Tedium] has a great retrospective now that the UK has decided to sunset ISDN in 2025. ISDN started in the UK in the mid-1980s.
ISDN offered two 64-kilobit channels that could be bonded to reach 128 kilobits. There was also a slower third channel for commands and signaling (although you could use it for data, too, using an X.25-like protocol). If you wanted phone service, your voice was on one 64K channel and the data on the other. No need to tie up your phone just to get online. Voice was digitized at 8 kHz with 8 bits of G.711 encoding.
One problem with ISDN was that it took a while to appear in the market, while conventional modems kept getting faster and faster. Despite having a theoretical maximum of 64k per channel, in reality, it sometimes topped out at 56K, just like an analog modem because of limits in the T1 backbone in the central office. In addition, cross-talk from the send and receive made long runs difficult. Someone eventually realized that it was because of the similar frequencies in use and that most people didn’t need the same upload speed as download. That was the birth of ADSL, but that’s another story.
For whatever reason, ISDN never really caught on. A common industry joke was that it stood for Innovations Subscribers Don’t Need. The truth is, the tech did offer more reliable connections and better voice quality. But in the end, it just didn’t pan out. It did spawn ADSL, but in the end, it was relegated to niche markets. Video conferencing and broadcasters used the technology and, of course, the phone company made use of it in a different way to manage the backend. You can see an AT&T video about ISDN below.
It is hard to remember when getting on the Internet was a technical project. Don’t even get us started on T1 which still topped out at around 1.5 megabits per second.
Interested to know what ‘cheap plans’ cost around the world, I’ve just had gigabit FTTH installed and it’s costing me £27 PCM.
ISDN in the UK was pretty good but so damned expensive, I had a client who insisted he needed an always on connection to the ‘net for email but ADSL wasn’t yet available and dialup was unreliable so he got ISDN2e and hammered it, then threatened to sue me (I still don’t know why he thought it was my fault, all I did was install and configure a mail server to his spec and got him to sign off on it) when he got the bill for his useage from BT.
Another site had ISDN30 which was a beast of a connection back in those days but even more expensive though it was used for telephony which was the lifeblood of that particular organisation.
FFTH = fiber to the home
PCM = per calendar month
ISDN = Integrated Services Digital Network (see article above)
ISDN2e = similar to above but different
ISDN30 = similar to above but with a bugger number, so it must be better
ADSL = Asymmetric digital subscriber line
BT = Bad trip?? Behavioral Targeting?? BlueTooth?? beat?? British Telecom (yeahh, that must be it)
However, after decoding all this I still have no idea what the reason for suing was. I expect that is is related to the fact that the line was based on time/data usage. But I have no clue about how much a nice figure and comparison would enlighten the story by a huge margin. Please enlighten us with some numbers. As you can imagine that since ISDN never really took of, nobody has a clue about the normal/expected/actual costs of this system.
“As you can imagine that since ISDN never really took off”
Hmmm.
That’s why I’m still stuck working with software that communicates over ISDN. That’s why there’s still routers that take ISDN on one side and VOIP on the other. That’s why BT is only just now planning to shutdown ISDN.
That’s why ISDN was only shutdown in 2019 here in Germany.
While ISDN for the end user wasn’t a great thing, large parts of the normal subscriber network were based on ISDN.
In Germany, it was common to have an ISDN connection with a small router. In the house you’d have normal telephones with plain old telephone wiring. The phones connected to the router which connected to the ISDN line.
56k modems depended on the existence of a digital (ISDN) distribution network. The 56k modems worked by generating voltage levels that matched the ADC outputs of the ISDN system. Without ISDN in the background, a 56k modem couldn’t work.
For those in the US, you may remember that there came a time when you could get three telephone numbers for your plain old telephone line. That was ISDN technology in the background. Private homes didn’t usually see the ISDN router – the conversion from the digital network to plain telephone lines was handled by the local phone company.
I am also from Germany. And back in something around 1998 to 2004 we were using ISDN for our home internet. It was also very common with friends and relatives. Maybe it was just in “our circle” a thing.
But as far as I remember a lot of people used ISDN at home.
A fun memory about it: Sometimes I used it, both channels for 128k, but my mom wasnt aware that I am at home+using the internet and she was awaiting a call. Of course this led to loud arguments between me and her…
Datex-P (X.25 service), CompuServe, T-Online/BTX/Datex-J, AOL etc also had an ISDN access throughout Germany.
Mailbox (BBS) operators often added an ISDN port in the early-mid 90s, too.
What’s also being misunderstood is that ISDN did at least reach 64 KBit/s or 128 Kbit/s (channel combining).
A 56k modem, by contrast, rarely reached 56k. In practice, it was waaayyy less. Say 28k8 or 14k4.
That was because telephone lines were quite noisy.
Here in Germany, we didn’t use twisted-pair landlines through and through, even!
Some older telephone cabling was unshielded DC wire. Thin, with bad insulation. Like from a door bell! “Klingeldraht” literally.
Way worse than like from a power brick or a loudspeaker wire.
Under such conditions, ISDN was way better performing than DSL or analog.
ISDN was digital, but used low bitrates. It had error-correction that worked reasonable on such an awful medium.
Let’s think about that for a moment.
Yeah, British Telecom.
ISDN2e, name of the entry level ISDN service from BT, the 2 denoted the number of 64K channels, can’t remember prices for install or quarterly ‘rental’ of line and the terminal adapter, useage was an extra charge on top of that.
ISDN30, slightly misleading name, the basic service was 8 channels but you could enable more up to a total of 30, more channels = more expensive,again can’t remember prices.
All the rest are pretty standard acronyms I think?
As for why legal action, he’d underestimated the cost of ISDN use and had received a quarterly bill which was about 4x (about £800 I think) the ones he was used to for his ‘old’ dialup line and useage.
ISDN got some traction with business users because it was faster than dialup, reliable and had service level guarantees but by the time the always on ‘net and email became a thing ADSL was rolling out across the country and was cheaper, faster if less reliable than ISDN.
The few home users I knew only had ISDN because their employer paid for the install and bills.
Regarding the acronyms, I was just fooling around a bit as I got carried away by the ISDN2e and ISDN30. Thanks for the extra ISDN and story info.
I recall 149 for install of isdn2 and about 27 monthly for both channels … Within a few quid and towards the end few years of the service
Welcome to the world of telco – as was told by my uni teacher for introductory telecommunications class – “the more abbreviations you know – the more senior engineer you are”
And this is still fine – try to read some documentation on how cell phone networks (any xG basically) work – that’s just mad. They really DO love their abbreviations.
Though – no mention of BRI vs PRI? That is actually interesting thing – as as different branches of telco companies meant different things by “ISDN ” – the one dealing with end users usually expected you want ISDN BRI and the branch dealing with customers with their own PBXes expected you want ISDN PRI when ordering “ISDN line”
As for billing, i don’t know around the world, but where i am (middle of Europe) BRI was billed per minute per channel and was little bit more expensive than normal phone line – BRI has two channels (+ separate channel for signalization, hence 2B+D) and for internet connection, you can use both of the for double the speed.
Side note
ISDN2 is BRI
ISDN30 is PRI in Europe – USA had only 23 channels
Yep, Basic Rate Interface (BRI) and Primary Rate Interface (PRI).
We had ISDN in Australia, and PRI was for some years the best way to connect a business PBX to the exchange. We started using ISDN before standards had settled and taken off, and then there was a year in which we switched to ETSI (European). Before switching to ETSI, we Aussies had the option of a “Semi Permanent Connection” (SPC) – a constant connection at a flat monthly rate.
I’m pretty sure ISDN was the mechanism within our original government-monopoly carrier for digital trunking, and effectively what most “circuit-switched” exchanges ran on for several decades.
BRI has 2x 64kbps B channel and a (16k?) D channel; PRI has 30x B channel and I think 2x 64k D channels, within a 2Mbps bearer. If USA had fewer (and smaller), perhaps they were fitting into a 1.5Mbps “T1” or something?
To my understanding, the higher data rates on analog modems relied on the “other end” being ISDN; the uplink was an analog transmission and topped out at ~30kbps (see Nyquist limits?) but the downlink was digital on its way from ISP/etc until coming out of the last exchange to the dialup/modem end. Hence it could often approach the digital throughput. However, ISDN in USA was only 56kbps IIRC, setting the target for modem makers. Also, using the full “digital” capacity would slightly overdrive the analog “last mile” cables beyond the specification for Telecommunications Network Voltage (TNV). Hence, at least in Australia, analog modems with digital-backed far ends were capped at 53kbps downlink.
ISDN2 (BRI) infrastructure could work with inline repeaters, powered over the signal wires, to increase the cable distance from ~6km to ~12 or even ~18km by cascading a pair of repeaters. At the time, digital data service (DDS, fixed point-to-point digital) or Frame Relay equipment for 128 or 256kbps only had the voltage tolerance to support one inline repeater, hence we could get ISDN at greater distances than other services of similar throughput.
Yes – PRI is runs on top of E1 / T1 – E1 is 32 timeslots that gives 30+1 as first timeslot is synchronization – maybe in Australia they used even the first timeslot for D? Don’t know. T1 is 24 timeslots, therefore ISDN will be 23+1 (they can use all 24).
When you look at ISDN PRI cards for VOIP, they are sometimes marked as E1/T1 and sometimes as ISDN but are basically the same.
The modem thing is interesting – i never saw the provider side of things during the dialup era – nned to read something about it.
I used to hang around a local ISP back around 1998 (they had a small computer store). They paid for a 1.5mbps T1 line that cost them $5,000/mo. Thats probably enough for about 50 concurrent modem users, but didnt get a really good look at what their server room looked like. I think service at the time was like $20/mo for unlimited. They were pretty much the only ISP in town, and things like AOL were long distance and extremely expensive
Pcm – pulse code modulation. Basically digital audio. A 64kbps could easily run a low bitrate audio stream in real time. A 56kbps connection wasnt steady enough or fast enough to live stream.
So DSL is the child of ISDN? I learned something new! 😁
In France, the cheapest offers (500mbps) cost from 30 to 40 euros depending on the operator (there are 4 and each have their own low-cost brand), but with options or added bandwidth it can go up to 60 euros.
Still in France, i pay 29€/month for fiber, full gigabit up/down, and including phone (though i dont use that). But this offer might not be available anymore (free mini4k).
$45/mo for 300mbit/s fiber here outside Boston, MA.
It shouldn’t be so slow or cost so much, but we have a hodgepodge of providers, many still using ancient analog CATV hardware. A national fiber initiative is, sadly, probably a long way off.
In some parts os Brazil you can get 1000Mbps for R$99,90 (equivalent to US$20); I have 500Mbps at home for that price.
I have gigabit fiber from CenturyLink in Colorado. Although it’s actually about 940mbits, since they use DSL. It’s $80 PCM with a fixed IP address.
~£30 gets you a VDSL2, sometimes with GFast, at about 80mbits without GFast, so FTTC.
FTTP is more expensive and gigabit class, which is rolling out across the country quite well.
My first broadband connection was 1mbit from Virgin, so cable.
Back then you got a USB modem and janky windows software.
I built a router out of an old Pentium 75, a pair of Intel 100baseT cards and LRP, the Linux Router Project.
Ran off a write protected floppy, except I also installed the packages for running a VPN server (pptp 😂) and packet filtering so that our http and gaming connections were low latency even while we were running high latency torrent and DC++ connections, which required you to install a second floppy drive because 1.44mb wasn’t enough space.
You had to install Virgin’s garbage client on your windows pc first, register the Mac address of the modem and then spoof it on Linux.
Good Times!
When I went to university I went from a 33k modem to their quad T1 line. 😨
Do you remember running a download manager because your modern would constantly drop connection and you needed to be able to contribute a download?
Yeah, from that to being able to download at over 1 Megabyte Per Second ☠️
So do all your downloading in the Comp Sci lab in a disconnected Solaris session (SSH into a SPARC somewhere) and then copy them to your zip disk or, later, their swanky new CD-RW burner they had one of and we’d all queue for.
Prior to that we got really good at using bzip to create tar.bz2 files split into 1.44mb chunks into a box of 20 floppies.
Or 1.6mb if you were feeling especially brave.
We’d play freeciv while waiting.
I learned about ISDN as a kid somehow, back when me and my brother were pulling down shareware from BBS’s and Dad would have used it to remote in to work. I also knew we didn’t have it, and almost nobody had it because it was priced too expensive.
We only ended up with it later during the era of DSL and DOCSIS when neither monopoly would come out to resurvey our house and bless it for service. But they would sell us ISDN.
I’m in the US and my broadband options are quite pathetic.
1. 768kb DSL via local phone company: $59.95/mo for the DSL specifically and $60/mo for a land line for grand total of $119.95/mo
2. Comcast/XFinity that is $50/mo for 200Mb (savings of $10/mo for automated withdrawl from a bank account otherwise it would be $60/mo) up to $110/mo (with $10/mo discount) for gigabit.
In 2024? Serious?? 😨🤢
It’s £30 for 80,000kbits here in the UK.
I am so sorry for you.
What about using 5G?
Is that a thing there?
What about Starlink?
I had two BT standard PSTN lines at home but with coming of internet I needed to keep the internet to be available when the BT line was in use. The cost of renting an ISDN2 line was less than the cost of renting the two PSTN lines plus the fee that was charged for a number of ‘free’phone calls. Thus if a call on either number was using one channel the other channel was ‘free’ to use for the internet. I ended up with a small Bosch ISDN PABX which still sits unused on the window cill! Once broadband came I moved to broadband and used VoIP. I still have a 1929 Strowger exchange which served a village in the North of England from 1929 until it was replaced in 1950 and survived until I found it sat idle in 1999 !
And here I was thinking we would be remembering Thr Future Sound of London’s 1994 release ISDN.
https://909originals.com/2018/11/28/electronic-conquistadors-how-future-sound-of-london-went-on-tour-via-an-isdn-cable/
I know it’s not on that album but…
We Have Explosives.
https://youtu.be/bUC4K3DsXug?si=3demz8UkHWKi_Zmn
We used to call it “It Still Does Nothing” mostly due to pretty much only modem available here (in Finland) for ISDN was PCI-card made by Telewell, which had horrible drivers. I remember fighting one computer for almost a week to get the internet going, since the drivers bricked the Win98SE upon installation and reinstalling windows took better part of the day back then.
AKA It Still Does Nothing.
Exactly, It Still Does Nothing!
It Still Doesn’t Network was what I heard when I was a contractor for the phone company.
My father, being a worker at Telefonica of Spain, got substantial discounts on their own services, so I had the luck to have ISDN through the mid 90’s until the early 00’s. Having two lines was a blessing in the household so I could connect to the internet to “work” without hogging the line.
The telephones included with the ISDN plan were really high end, for the era; mine had an integrated switchboard (so I could direct a call to another phone in the house), modem, agenda (so the caller ID could show names instead of numbers). I could even send faxes from my computer through the phone!
And while it was not much faster than 56k modems, it was more reliable. Connection to the ISP was almost instant, and because it was all digital, sustained speeds were, in general, better.
I won’t say I miss ISDN, at least not the internet part, but certainly it was the best phone experience ever.
Ahh memories. My ISP at the time (BT) allowed free unmetered connections with just one 64kbit/s channel. Using both channels bonded at 128kbit/s was very expensive. After some playing about we realised we could simply dial out twice on both channels, two unmetered 64kbit/s channels with a Linux-based router handling the load balancing between them. Worked a treat!
The issue with ISDN was that it was such a cash cow for BT, it stopped them upgrading the infrastructure to use other technologies meaning the UK was in the internet slow lane for a long time
BT were a really odd organisation, they did some incredible research and development, their Martlesham Heath labs for example were at the forefront of and even created new technology but, by turns, pretty much everything BT ever did for consumers was horrendously expensive and their monopoly on telecoms services in the UK held us back years.
That happened everywhere. ISDN and 56k modems were billed by time of use, which made telcos resist the upgrade to ADSL to the last possible moment, especially where they had local monopolies, which they did almost universally.
In our home town, you could get ADSL if you wanted to, but the last mile was owned by a different telephone company to the one selling the subscription, and they charged by the minute – so you had to pay two different companies for the same thing. No can do. It took several changes in the law to force telephone companies to apply “reasonable rates” to competitors. Otherwise all the small towns would still be on dial-up.
I used it in one job for remote workers and regional offices up to about 15 years ago when there was no other broadband options.
I have a recollection of pricing installation of ADSL IN some rural locationS and it costing the GDP of a small nation to get ADSL broadband but an ISDN would be set up for a negative exponential of the cost.
I’d like to say a lot has changed but in a lot of rural locations here in Ireland your best bet is cellular based broadband (luckily they set up a 5G antenna nearby in the first months of the COVID pandemic or id have been on 1 mbit) or Starlink!
Anyway I’m sure I still have an ISDN router and thin client around here somewhere as a spare for when I had to do remote visits!
Those were the days, I remember paying double to get two channels and enjoy 128 kbits!
That was so insanely fast, I could not imagine anyone would ever have such a speed available 24/7.
ISDN failed for consumers in the US because the service was expensive. the bells charged per minute, even for local calls. 56k modems on normal land lines didn’t have that problem so that is what folks used.
I think it’s also because the USA were a third-world country at the time, as far as infrastructure was being considered.
Water, power, landlines.. A huge country full of oudated, crumbling infrastructure.
No offense. Upgrading this is behemoth of a country is quite a challenge, simply.
Here in Europe, the countries are much smaller, by contrast. Changes can be done easier here, technically, if politics and bureaucracy don’t get in the way.
Yeah, tell me how great telephone service was in the late 1980s to 1990s in Germany.
It was common for US soldiers to be stationed here, get an apartment, apply for a telephone connection, and not have a telephone installed before they were transferred out two years later.
Local calls were charged by the minute at that time in Germany – while local calls were part of the monthly fee in the USA.
Um, why do you constantly feel the urge to “pay back” in some way or another? 🤷♂️
What I wrote wasn’t an anti-USA comment, whatsoever.
I merely mentioned an explanation as to why ISDN didn’t catch on over there. It’s because of huge investments that come with it.
And a phone company like “ma bell” surely wasn’t eager to invest in modern tech. In another article here, it didn’t replace telephone exchange that burnt down by a modern, solid state replacement. Instead, the same old technology was being deployed. The event happened in 1975, when DTMF phones were around already.
Here in Germany, in the 80s, the Deutsche Bundespost started to replace all old equipment with digital phone exchange systems.
On a large scale.
In the early/mid 90s, all 0130 service numbers were entirely free of charge (they still existed back then).
The national online service, BTX, even had a free guest access (“Gastzugang”) since the early-mid 80s. Guests could try out BTX everywhere and even participate.
All pages that didn’t cost money or were paying the BTX fees for the user.
Quelle, Telefonauskunft and Deutsche Bahn were popular BTX pages at the time, I believe.
Home banking , too. Computer fans visited the pages of WDR Computerclub.
All this in the 80s, already. 😁
But yes, it wasn’t all rainbows and unicorns, we had problems, too. Especially after reunion.
The landline cabling in East Germany were very very poor, it barely worked for ordinary phone calls (remember “Faßen Sie sich kurz” slogan of DDR/GDR).
That lousy infrastructure caused issues with FAX and BTX.
Our West German “Telekom” (sucessor to Bundespost in telecommunications) had to massively upgrade that rusty old infrastructure. Not to say replace it completely.
It goes without saying that all the massive investment for former East Germany and its citizens had lowered our living quality and harmed BRD’s economy on the long run.
It’s not their fault, of course,
and we didn’t blame them, initially. Because we felt sorry for them at the time and wanted to have them with us.
But they don’t want to hear that side of the story, whatsoever.
They’re always (often) playing the victim card on us.
That’s at least my opinion/experience. I’m gladly proven wrong.
But a friend of our family is from ex GDR and acts same.. *sigh*
For example, they often blame(d) us for the unfair treatment in the 90s labor market and for being arrogant.
And for the Treuhand story, in which GDR stuff had to be sold off for “cheap” (which wasn’t untrue, but their 50 years old stuff simply wasn’t much worth anymore by western standards. Time pressure was also a factor).
Anyway, back to USA. Up until a few years, the USA simply had a bad infrastructure, or so we were told. It’s not my fault, whatsoever. 🤷♂️
a) The US power grids were prone to domino effect. Remember that 2003 outage. Here in Europe, an outage on that big scale couldn’t happen at the time, because of buffer zones.
https://cleanenergygrid.org/americas-third-world-energy-grid/
b) The tap water wasn’t/isn’t exactly drinking quality. I heard in some places people have to boil tap water to make it drinkable. In such a big country, that may be the case, whatsoever. It shouldn’t be the norm, though. Not in 21th century. Private water companies are a strange concept to me, too.
In Germany, tap water has to meet strict requirements and is being checked by government/city on a regular basis. Money thinking cannot get in the way here.
c) Some of the US landlines were (almost) from the times of Mr. Graham Bell himself. In Germany, telephone lines are often underground, not mounted sky-high on wooden telephone poles in the Pampas, as with infrastructure in Latin America.
Anyway, I was talking about the past here. Nowadays, the US may have modern infrastructures.
Although I heard they nolonger seem to use stationary telephones at the workplace very often. That’s a step back, I think.
Here in Germany, a telephone is a basic requirement in offices.
Fax machines, too, as a hidden feature of multi-purpose devices (scanner, printer, copier, phone).
Often, if someone has a quick question, we do make an old fashioned phone call.
Not via MS Teams or an e-mail, but verbally real person to real person.
“It was common for US soldiers to be stationed here, get an apartment, apply for a telephone connection, and not have a telephone installed before they were transferred out two years later.”
Okay, yes, that’s a valid criticism.
It wasn’t being limited to stationed personell.
Ordinary citizens had to wait a longer time, too.
Had to do with incomplete deployment of landlines at the time, I think. It wasn’t same in all cities.
But lack of phones at homes weren’t that of an issue, there was no panic if a phone was unavailable.
Public phone booths existed in many places already.
CB radio was very popular in the 70s/80s, too.
GDR was worse, also. I was told some GDR citizens didn’t even ever had their own telephone before the 90s (!) – when most of us had explored BBSes for years or had an internet access (1&1 was an early bird). Hearing this was mind blowing.
Western North Carolina, USA
$80+ per month for a poor 6mb ADSL :)
That or maybe dialup?? Life sucks here.
£30 a month gets you FTTC or FTTP here in the UK.
So that’s 90mbits or 900mbits.
And the UK is still slow compared to mainland Europe.
I can’t believe America is still this far behind.
And it’s not like you don’t have the space to lay fibre.
It’s really hard laying it here in the UK because it’s so dense.
When I first started working for my current company in 2004, they had 100 people in the office and a single T1 line serving them Internet. Still remember the prohibition against streaming video or audio. I once asked the IT guy what the 1.544 Mbit/s pipe cost. It was THOUSANDS of dollars a month! At the time I was paying $80/mo for 80 Mbit/s at home. Such was the cost structure at Ma Bell for commercial grade connectivity.
:: puts on a pair of ‘devil horns’ :: Yes, but how reliable was that T-1? the bulk of the cost was the service guarantee, I can assure you. :D
Residential service was “oh, it’s down. We’ll pencil you in for the fifth tuesday of next month between 9:00 and 9:05 PM for the initial diagnostic”, whereas business lines were “Oh, it’s down? truck’s on it’s way, give them fifteen minutes because there’s an accident on the freeway they have to route around; and we’ll give you a service credit for each hour that you are down.”
At least that was my experience with the local telecomm, who has changed their name at least four times since I started my career in IT back in the late 90’s.
And then they wondered why the local cable companies started eating their lunch with residential internet for the past ten years…
The T1 was dedicated to that company and always available, whereas your 80 Mbit/s was shared by 800 other customers who all paid for the same bandwidth reservation on the network, leaving you each with a “guaranteed” bandwidth of about 0.1 Mbit/s.
One more thing in favour of ISDN is that the time to connect was fast enough to have internet on demand.
I had my Linux setup to establish the ISDN connection to the internet provider as soon as a packet wanted to travel in that direction.
Basically the feeling of a permanent internet connection without (most) of the expense.
was nice, but prices were too high, and it became obsolete very quickly.
I spent days trying to order ISDN from South Central Bell (AT&T in Louisiana) in the early 1990s…I never was able to find anyone at the company who knew what it was…much less order.
Yeah, I had ISDN from two different Bells in the 1996-2001 era, and ordering/installation/initial bring up was a complete PITA. I expect they lost a lot of wealthy customers who could’ve paid, but weren’t willing to deal with endless bullshit. (whereas i had more time than money or sense.) I got to the point with Qwest where I was asking for employee IDs every time I called in, and reciting them back, so I could have some documentation about who said what when.
Here in Germany ISDN was quite a breakthrough for private access to the evolving internet. Being limited to 56k modems (which never actually reached 56kbaud) had been a pain in the body’s rear end.
You could also benefit from telephony features mostly unavailable or more expensive on pure analogue landlines, like multiple subscriber numbers, terminal portability, free D-channel messaging, call forwarding, conferences, immediate charge information etc.
It was kind of a breakthrough for the AVM company which produced those affordable “Fritz” ISDN cards. We saw lots of customers switching from “industry grade” cards to Fritz due to stability and driver issues. Remember, Windows still had DOS underneath, with rather unstable “plug & play” configurations.
Sending a FAX with both sides using native ISDN solutions was faster than ever before. Civil administration jumped on it. Especially those that already had X.25 WAN solutions up and running were able to migrate easily (as long as their solution provider supported it).
Then there was the case with those travel agencies. As a consumer you weren’t able to digitally book a flight. All was controlled by host applications. Agency users operated on those (in?)famous Siemens 3270 terminals which were optimized for packet switching, which itself was used for cost reasons. Dialup lines either weren’t fast enough, dialin times too long or just too expensive.
ISDN was quite a game changer here. There were even implementations of Ethernet-over-ISDN which weren’t that comfortable but able to replace expensive multipoint WANs.
Though the ISDN era was a rather short one, it really helped re-thinking many solutions. Being limited to one single infrastructure provider and strong standards definitely contributed. When DSL came up many companies already had strong ideas about WAN communication.
Fun fact: I still pay a few bucks for the now obsolete ISDN features, but the old contract is cheaper than any new one.
How could you use the D-Channel messaging? I know there was a service that checked your Mail (you gave them your password) and when a new mail arrived, they contacted you via D-Channel so you could go online and fetch your mail. But was there a way to simply D-Channel Chat with someone else you knew with off-the-shelf Fritz! Cards?
I know there was a time when a D-Channel flat rate was supposed to be available at 8kbit/s (?). I thought about using that as an upstream channel to some satellite Internet provider, because they had a quite ok downstream and price was ok. (But high ping.) But you still needed an uplink channel. But AFAIK the D-Channel was never truly used for internet.
“Here in Germany ISDN was quite a breakthrough for private access to the evolving internet. Being limited to 56k modems (which never actually reached 56kbaud) had been a pain in the body’s rear end.”
Yes, the Bundespost (before Telekom) somewhat tried to push it through since the 80s.
Pilot projects started in ~1987, when Bildschirmtext (BTX, later Datex-J) was still a thing.
– In 96 or so, the T-Online software 1.2 (Mac System 7, Windows 3.1) added KIT support for BTX, even.
That was a replacement for the old CEPT pages, essentially.
With ISDN, this new technology worked blazing fast. 😃
Even little pictures were instantly loaded..
Unfortunately, the internet got in the way, eventually. X.25 got replaced by TCP/IP, T-Online software by WWW browsers loading big fat websites. Ads..
We Germans had “internet” before the internet, and ISDN was the foundation.
Btw, some German versions of Windows 3.1x and 95 shipped with ISDN support.
They had TAPI support, essentially.
It was being featured on the box art, even, I think.
Or CAPI, rather..
https://en.wikipedia.org/wiki/Common_ISDN_Application_Programming_Interface
“ISDN was quite a game changer here. There were even implementations of Ethernet-over-ISDN which weren’t that comfortable but able to replace expensive multipoint WANs.”
Indeed. ISDN was a serious, rock-solid technology.
Otherwise, the Deutsche Bundespost wouldn’t have chosen it.
That agency may have been a slow, bureaucratic behemoth, but it wasn’t stupid.
The technology it operated was functional and designed to be foil-proof.
Its infrastructure was its holy grail, after all. Considering its hostility against early modem users and users of unlicensed foreign telephones, it must have been really caring here.
ISDN, combined with fibre glass (the 80s era type) was considered the future.
Unfortunately, then Telekom, T-Net, T-Mobile and T-Online came to be in the 90s.
Somewhere in the late 90s, the euphoria and eagerness for modernization changed over to, um, what we have now.
I think I don’t need to describe what sort of company Telekom has become or how it thinks about investing in a good infrastructure.
PS: To my understanding, fibre was even planned as early as the 70s, along with videophones, but it lost to cable TV. Because, what could possibly be more important to us than the holy “Flimmerkiste”? 🙄
So the founding money got invested into cable, so we can watch Tatort, Sportschau, Theaterstadl and Lindenstraße. Greeeat. 😒
Oh isdn is dead you say? Pls tell that to PBX operators and other telephony operators. They’d be suprised
If you note, in the article I mention that they use ISDN in a different way in the back office. But what normal subscribers mean when they say ISDN is the subscriber-level ISDN and that has always been a niche for data communications to the home or office at least in the US.
I was thinking the same thing. The article refers to what was called BRI service in the US and was mostly residential, with 2 bearer and 1 data channel. A whole lot more PRI service, with 23 bearer and 1 D channel provided on a T1 local loop, is likely still in use for PBX trunks.
In 2000 I had to use iDSL because I couldn’t get other forms of Internet (in the Bay area, nonetheless.) I used Megapath DSL. It channel bonded 2B+D to give me 144 kbps. Megapath was wonderful to work with. The cable and phone companies were not.
It was transformative less for the improved bit rate, but because it was always-on. The modem/router had PPTP capability, and it was so wonderful to be able to access my machines at home over vpn from work or wherever.
Used to work for BT R&D in Martlesham, Suffolk back in the day when ISDN was really still a thing and ADSL wasn’t.
May be pure coincidence, but I always thought it suspicious that the main railway line out of London that served Martlesham (Ipswich) has the following stations in this order…
Ipswich
Stowmarket
Diss
Norwich
Methinks some engineer at BT might have been having some fun in the standards body?
Oh ISDN. It brought back this memory: I installed many Cisco dial on demand ISDN routers at travel agencies that used them to connect to touroperators. One agency didn’t want to buy an expensive Cisco and as we only offered that one they decided to buy some other and have it installed by another guy. That fellow made some mistake, probably the name/password combination so the connection was made via the telephone company, wrong credentials exchanged and the connection was dropped. After which the router immediately tried again….. Now the Dutch telephone company (PTT or KPN, don’t remember) charged not only for minutes connection time but also a 10 cent starting tarrif. And with ISDN you didn’t hear a thing. The poor thing tried 120.000 times before the bill came. Of course they did notice that it never made a connection but not that it kept trying. It was during the time most travel agencies still did almost everything via voice calls so business continued. I have never heard what they said to the guy who installed the other router but we installed a Cisco soon after the bill came.
ISDN30 is a Primary Rate Interface (PRI) consisting of 30 64kbps bearer channels (B channels) and one 64kbps data (D) channels. This was sometimes referred to as an “E1-carrier”. The North American equivalent was T1, which had only 23 D channels.
ISDN2 is a Basic Rate Interface (BRI) consisting of two 64kbps B channels and one 16kbps D channel.
The data channel is primarily for signalling purposes. Although it was possible to access X.25 services over the D channel, it was much more common to use one or more B channels as this was faster and easier to bill for. There were some specialist applications using the D channel such as card machines.
Ooh I ‘member!
We had a ISDN connection for some time. Had a 486 and a ISDN card with fli4l linux distro on a disk and we could control it with the small fli4l application from out desktops. Unfortunately ze germans couldn’t translate the documentation to English, so it took some time to configure it. Does not seem to have gotten any better in that regard. Scheisse!
Hi, sorry about that. I believe I know that sort of Germans you’re referring to.
Not all of us Germans are like that, though. Some of us spoke English fluently for decades by now.
Especially the more technical inclined ones who had to to resort to English literature.
The reason why English wasn’t so common is because of Latin, French and Russian.
Older generations had to learn Latin in favor of English.
Then there were the occupation zones.
Citizens near France rather learned France before English.
The former East Germans (DDR), by contrast, were being indoctrinated to learn Russian.
In addition, we rarely had English on TV. All shows/films from USA, Italy, Spain, France etc were being professionaly dubbed.
Being a voice actor was a real profession in Germany early on.
It wasn’t until Zweikanalton or anslog Satellite TV, that you could switch to English audio / Original audio.
So it wasn’t entirely these oldtimers fault that their English was so, um, humble.
Several circumstances lead to this.
Don’t worry, i know there are Germans who speak good English, it was just a little jab at fli4l. I’ve had the pleasure of meeting few Germans with good English skills (shout-out to Oliver).
Glad to hear! ^^ Most of us here do shudder whenever one of our politicians has an English speech, btw. We don’t know whether we should laugh, or cry innerly. 🥲
I vaguely remember fli4l, a friend of mine used it with a 1000 DSL connection. He was one of the first I’ve seen who had such a a fast interenet connection.
He had 5GB to use “for free” (I guess at least 50€/$ per month) and after that every MB took money. He attached a HD44780 with a traffic counter and a have-to-pay display…
There was always some difference between his calculations and the bill. He started to argue with AOL, but I can’t remember if this led anywhere…
This guy also shared movies when we were physicially at his place. This was also done by the fli4l router/server. The program/extension to fli4l must have been samba, but was called something with “ice”.
All this happened somewhere around 2005 IIRC.
One use I haven’t seen mentioned yet was ATMs. The would use them in a 0B+D configuration (no bearer channels, just the signaling channel). It was significantly faster AND cheaper that using a dial up modem, because the amount of data being sent was super small, and the digital handshake to send the data over the D channel occurred when you powered up the modem, rather than when you placed the call.
I ruled the Quake 2 servers so hard, once I got ISDN and a modem that properly supported 128KB bonded channels. :D
Before that, I had another big step-up. I was always struggling with my 56K modem. Never reached anywhere close to full speed, always lag compared to others.
Until someone gave me the tip to connect my computer to an outlet that had a proper Earth connected. That made all of my problems disappear. Good times. ;)
ISDN was great back in the 90s when I worked at a radio station. It was often the easiest way to get decent quality audio back to the studio from events.
Ah, ISDN ;-) As others have already mentioned, ISDN was quite a success in Germany, at least for the years between 56k modems and DSL. I started with ISDN in the late 1980s. One of the first “killer applications” back then was home banking via “BTX” (the German Teletext System). Before ISDN, you could essentially read the text as it appeared on the screen. With ISDN, the screen content was there “in one go” – it seemed like science fiction to me. Just a few years earlier, I had started my online life in the BBS scene with a self-soldered 300bps modem (= 0.3 kbps / 0.0003 Mbps). Which was highly illegal in Germany at the time ;-)
I still have that Draytek Vigor ISDN-USB dual channel adapter – of course translucent, to fit the Blueberry iMac.
+1
BTX was great, despite not being accepted by the crowd of the time (=simple minded, techno phobic citizens. The mortals, the “Normalsterblichen” 😁).
My dad used T-Online Classic (essentially BTX or Datex-J) for homebanking for a long time (until it was being discontinued, in fact).
The old X.25 connection was much safer than using an internet gateway.
And more efficient, due to lack of bloat.
Home banking was an external database resource to the BTX system, I vaguely remember.
The bank computer could initiate a secure connection the PC.
Datex-P service was used to connect ATMs, too, I believe.
Datex-P was the terminal service, essentially. A packet oriented network.
Here in my city was a local PAD you could connect to, with as little as an acoustic coupler and a serial ASCII terminal.
BT applied DACs to my line, 56k became max of 28k, took 18 months for them to admit they had shared my line, no apology and no proposals to remove it. So I ordered a business ISDN line through a third party with no excess install costs and got 128k after bonding using software. BT have been on my never use ever since.
A lot of Telecom techs used to say it stands for I Still Don’t kNow. They said lines would have problems for during install and the only solution would be to set up ISDN sub racks inside the building.
@Al Williams said: “We are definitely spoiled these days in terms of Internet access. In much of the world gigabit speeds are common and even cheap plans are likely to be measured in 100s of megabits.”
I dunno where you live but here in S.E. Florida USA Comcast/Xfinity has what effectively is a monopoly in “broadband” internet with its DOCSIS hybrid fiber-coax (HFC) network. I get 250 Mbps down and roughly 25-50 Mbps up internet access and a cable TV service that is unwatchable. To squash competition my data is capped by Comcast at around 1-2TB/month. For all that I have to pay around $220 USD per month. AT&T is an ISP in my area but they make Comcast look benevolent by comparison. A cellphone provider (T-Mobile?) was supposed to roll out 5G “wireless broadband” to the home – but it never appeared even after years of waiting. Starlink is overpriced and fades out when it really rains hard here (often).
So that’s it where I live; less than mediocre capped internet service for gold level prices, and zero competition amongst ISPs. If I can prove I am an illegal migrant, the whole story is flipped on its head – free everything forever – as long as I vote for a certain political party.
I ran a small ISP using 64k ISDN, and five 9600 baud dialups. Back in the 90’s people wanted 24/7 connections with static IP. I could give them each multiple IP blocks, and their applications ran fine at low bauds. Cable modems finally put me out of business. By then applications were high bandwidth, as the Web took off. I seem to remember the cost being $70 a month for ISDN and $150 a month for Internet routing. I just had a Linux server, ISDN router, and Cisco 8-port dialup router to mechanize it all.
I call bullsh*t on this:
“Despite having a theoretical maximum of 64k per channel, in reality, it sometimes topped out at 56K, just like an analog modem because of limits in the T1 backbone in the central office”
AFAIK ISDN2 channels were similar (but cheaper) to what BT sold as Kilostream, and with both of those you got exactly the same fixed bandwidth all the time unless something went badly wrong – ISDN2 was a direct link into 2 64k channels on a 2MBit link in the exchange, and again these did not change in bandwidth at all ever. They got muxed into 8, 34, 140 or 565 Mbit PDH links and trunked around on fibres to the nearest switching site(s), later those same 2Mbit links were muxed into SDH and eventually their bloody stupid IP core.
I suspect any variance in bandwidth would be due to the user’s equipment, their ISP, or general network overhead.
Totally different to ADSL which was a best-effort sort of affair and something of an outlier for almost everything else BT sold into the 2010’s which were almost always fixed bandwidth “pipes”.
On all ISDN standards a B channel is ALWAYS 64K.
I bet the 56k limitations was due to the use of a PSTN modem over a B channel, thing many did.
In Italy for example ISDN was mainly installed using a TA a/b embedded in the NT and thus the only “data” connection was done simulating a PSTN line over a B channel, thus the “limit” of 56K.
But an ISDN B channel, PRI or BRI, is 64K.
So the limit was NOT in the central office but on the customer premise because the installation of a TA a/b
“In much of the world gigabit speeds are common and even cheap plans are likely to be measured in 100s of megabits”
…laughing in despair and Comcast monopoly….
Ok, first I used ISDN when my ISP got off the ground in Dallas, Tx. I was at the “end of the bleed”. So we opted for ISDN, I think I had at one time six of them, and three of them were bonded together via my Cisco 7507 router. I still have my Trend blue butset.
Im sorry but I have never heard of “Innovations Subscribers Don’t Need.” everybody that I knew called it and it is a slur: “I Still Don’t kNow”. BTW I try not to redo the past. Even though without it we are bound to repeat it…. ~~ Cris Harrison http://www.phoenixcomm.net
“Similar frequencies in use and that most people didn’t need the same upload speed as download. That was the birth of ADSL, but that’s another story”. Is there information – like this video, on how ADSL, or VDSL works under the hood?
ADSL: https://en.wikipedia.org/wiki/ADSL
VDSL: https://en.wikipedia.org/wiki/VDSL
Why waste bandwidth on a video when the text and drawings are sufficient?
Well, first of all ISDN did took off around the world and ISDN was the base for many “new” protocols that in the end allowed to have what we have today.
In many nations ISDN “failed commercially” mainly for the stupidity and greed of telcos and because to deploy on the territory a technology needs a lot of time and information for the public.
If a telco in a nation doesn’t understand a technology and its advantages, no wonder is not fully adopted.
The disinformation to the public in many nations about WHAT was ISDN and how to use it at the best, was one of the major problems.
IN the late 90s I did write and maintained an ISDN FAQ that amazingly is still online (sorry, only in Italian – http://web.mclink.it/MC4880/ISDN/index.html)
Moreover, at the same time ISDN started to really be deployed, ADSL arrived, using the same media.
Instead of 128K, ADSL allowed for much more (at least in downstream) thus many wanted it rather than ISDN, ignoring other advantages of ISDN (mainly never explained by the Telco).
In Germany for example, one nation where ISDN really did took off a lot, was even born a standard ADSL + ISDN on the same wire (BRI only of course)
My point is that ISDN “failed” commercially in many places for lack of marketing support from many Telco but it succeeded to be the FIRST worldwide standard in telecommunications, is the base for many other technologies, still used in many dorsal (PRI) because its reliability and flexibility.
I did work 20 years developing and maintain an ISDN stack, deployed and used all around the world.
It is the end of an era, sure, but ISDN was immensely important in so many areas and lot of fun to work with.
I remember (mid 90s or so) when my high school (private school and not exactly cheap) got a 64k ISDN link (although back then I didn’t know what that was) and I remember talk about how they could “double the speed” (and not realizing at the time that it was more expensive as well as faster). These days the same school probably has a fast fiber link of some sort.
So many memories of time spent at lunch and otherwise up in the labs browsing the internet.
In my country (Slovenia) our main telco was taken to court because they forced ISDN on customers who wanted to get ADSL. So glad I never used that telco.