Ever Heard of “SIP”?

by | Jul 1, 2014 | ISDN | 4 comments

sipWell, I hadn’t either…so if you’re like me, then you’re about to learn something more about the demise of ISDN.

You may or may not know that throughout most of Europe, ISDN had an earlier stronghold, was more widespread, and more a part of the hard-wire phone system than it EVER was in the United States.  ISDN was commonly used to displace the older technology of equalized analogue landlines in the UK.  ISDN in France has widespread availability, especially in rural and outlying areas (!).  Germany’s ISDN penetration is popular with an installed base of 25 million channels.  And yet, even in Europe, ISDN is losing its grip, and is being replaced by IP solutions.

Below, you’ll find a link to an article on SIP (Session Initiation Protocol) Trunks gradually replacing ISDN.  In fact, the first sentence of this InfoCom article says it all:  “…Because of the general trend towards IP, SIP trunking will prevail in the long term and eventually replace ISDN as it offers a series of advantages: granularity, flexibility and centralisation, that is, cost savings…”

I don’t pretend to know much about the intricacies or concepts behind these esoteric fields of business and telecommunications infrastructure, but I get the drift.

And forgive me for concentrating on this so much in the blog lately.  We are in the middle of technologically-advancing forces that can slip past you if you don’t see the indicators.  SIP in Europe is one of those harbingers.

Here’s the link:  http://www.virtual-strategy.com/2014/06/27/infocom-illustrates-advantages-sip-trunking-replacing-isdn




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  1. Joel Richards

    Interesting post. I did not realize how prevelant ISDN still was in Europe. About six years ago, when I was still moonlighting in the IT world, I looked at moving a client to SIP telephony.

    SIP is the foundation for a lot of the VOIP (voice over internet protocol) telephony. I hesitate to say all because there are so many services like Skype that I suspect use SIP to connect with landlines but also use propretary technology to make connections. If you go to an office and see grey CISCO phones on desks that company (either locally or remotely) is running a SIP server.

    Using SIP vs ISDN has all the issues of using a non-dedicated VOIP service (like Skype) vs ISDN. Aside from quality of the codec (VOIP services and I assume SIP providers too) which has about reached parity these days, SIP is not a direct digital connection like ISDN. It isn’t rock solid and it is (theoretically) suspetible to the digital “interference” of communicated over the internet.

    So I believe SIP will not replace ISDN for voice-over artists. If it could it would have already. I do think as voice-over artists we need to concern ourselves about how the FCC is (or is not) regulated internet service providers. Regardless of who or what takes over for ISDN it will be internet-based and we will become ever more dependent on internet service providers who provide the worst service of any developed nation. Europe already has us beat there too.

    • CourVO


      Thanks for your reply… I much appreciate your taking the time to analyze that and explain further. This is why I should probably stick to less technical posts. Still, I think the writing is on the wall for ISDN, globally.

      Thanks again for commenting.

      Dave Courvoisier

  2. Roger Woods

    ISDN in the UK is dying at an alarming rate if like me you live in rural location. Space in local telephone exchanges once reserved for ISDN equipment is rapidly being taken over by ADSL and fibre optic kit with the rapid roll-out of fibre to commercial and residential properties offering data speeds up to 150mbps. Even in major towns and cities with broadcast hubs, even London, ISDN is becoming increasingly move difficult to have installed. IP is therefore the way to go. I have an hardware codec with ISDN/POTS/SIP & IP connectivity options although I’ve not used ISDN for almost 10 years. Software IP codec are fast replacing ISDN, Source-Element NOW and ipDTL use RPT code in Googe Chrome to allow real time low latency bi-directional audio, I’ve these too and they sound great and in the UK more VOs are switching to these when they get a withdrawal of service note from our national telecoms provider that there ISDN is being turned off. Luci Live, Report-IT, the companion iOS from my codec, and Access from Comrex are handy tools for broadcasters, journos and VO’s on their mobile phone with access to WiFi. The writing is on the wall for ISDN, it’s an old technology as data needs to move faster than 128kbps. It’s also very expensive!


  3. Nathan Lang

    Hello Dave, I wrote up an article (http://iam.nathanlang.com/ipcodecs) on my blog back in July of 2013 somewhat lamenting the demise of ISDN service in my area. NYC was hit hard by superstorm Sandy and Verizon had problems at its main copper site. Being no stranger to adventure, I purchased the Telos Z/IP One and sought to work out other connection options outside of ISDN my other go-to tech: Source-Connect. I set out to find an alternative specifically for me and others like me: Voiceover Actors. As you might expect, the foray was not without headaches!

    In any event, I learned a great deal about SIP and possibilities that the future holds for it. Turns out that much like the ISDN interoperability standards, this tech was (sort of) mandated to guarantee minimum connections with other hardware/software SIP codecs. Widespread use of this technology (while not there yet) could ante up the user base considerably. I reached out to all the major tech manufacturers (both software and hardware alike) to establish minimum working protocols for SIP and RTP connections. Let me tell you, the results were fantastic.

    Still, if Studios, Engineers, Directors and Producers don’t embrace the technology sadly it will be relegated to its original intended audiences: STL – Radio Station Studio-Transmitter-Links. Another part of the problem is this: Manufacturers want to insure that you stick with THEIR codecs. So, if you buy a Telos ZIP one, Telos can guarantee rock-solid connections with other ZIP ones. Thankfully, Kirk Harnack and the other guys at Telos keep their ears to the pavement ensuring a well-rounded interoperability plan. I think until ALL the tech plays together nicely. ipDTL connecting to say, a hardware codec (which I’m told there are possibilities now). Until my codec can dial up a SIP or RTP address on say, Skype or Source-Connect NOW, or dial into Mo Dutta’s STL-IP codec. Or, Sound-Streak allowing for SIP connections – well then, this all stays proprietary. Not very useful when its goes up against tried and true ISDN.

    Thankfully, bridging services exist like Dave Immer up at Digifon that can link these disparate services together. But truthfully, Producers just want to book in this day and age without any additional drama.

    All of the manufacturers I reached out to offered (if it were possible) various ways to establish minimum VO connections (MPEG L3 48K) I use via ISDN. The ones that were realistic were clunky at best, needing a SIP server to establish the connection. Then, there are the firewall (NAT) issues. Lets just say we will leave that for another post. So, in a not so short post – YES this technology is real, YES this technology works. Once the interoperability standards are fully worked out, and actors don’t have to buy into proprietary hardware/software it will be a much different conversation. I urge all vo actors not yet familiar with this tech to reach out with any questions.



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