Setting Up ISDN for Voiceover Work

Thanks to Johnathan Turner for getting in touch with this question: “I’m looking to get ISDN for my voiceover work,  but don’t know where to start!  I’ve been turned down for work because I don’t have a ISDN connection. How does it work? How do you I get it? And is there a better way?”

OK Jonathan – We’ll help if we can… but I suspect you won’t like what we have to say…

What is ISDN?

ISDN stands for the rather snappy “Integrated Services Digital Network“, or, somewhat unkindly, “It Still Does Nothing”

In the 1990’s, ISDN was cutting edge technology. It bridged the gap from old slow dial-up modems, and the fast broadband access we have today. You could get an ISDN box installed fairly cheaply, and it had 2 x 64kilobit/second RJ45 networking connectors. If you chained them together, you could get a solid and permanent 128k Internet connection without waiting for a modem to connect. Many used them at home (using the  “Home Highway” service), and many businesses used them as a low-cost way of networking services between two buildings.

An ISDN line would be installed by BT engineers, replacing a standard phone line socket with an ISDN box (with data and phone line sockets). The box was about double the size of a standard BT master socket. Pictured here is a very grainy shot of three ISDN boxes at a radio station in the South of England. Sorry – best shot we have!

Picture of three ISDN line boxes on a wall

Picture of three ISDN line boxes on a wall


ISDN for Audio

ISDN wasn’t limited to surfing the net though. It was (and still is) used for broadcasting and audio work. Essentially, it was a case of plugging a special box into your ISDN line, and having a similar box at another ISDN point somewhere else. The box used clever software called a CODEC, and was typically used for the following:

  • Providing travel news for radio stations (AA Roadwatch, Metro Trafficlink)
  • Radio News and Sports reporting (ISDN points were often installed at key buildings and football stadiums for reporters)
  • Voiceover work
And we guess that last one is the one you’re interested in, possibly as part of your home recording studio.

Why ISDN for Voiceovers?

In the olden days, voiceover would have to rack up the miles driving to recording studios and radio stations to voice scripts face-to-face. ISDN changed all that, and many travelling voiceovers set up home studios with ISDN and fax machines. Scripts would be faxed (or, now, emailed), and the recording studio dials in, and conducts the recording session over the ISDN line. The circuit supports two-way chat, so the studio producer can prompt the artiste to read the script again in a different way.
ISDN keeps the costs down for the studio, and the travel costs down for the voiceover, and it tended to be that those with the ISDN kit, got the work! Wonder how many ads and corporate videos have been recorded in boxers and vests in a bedroom?

Getting an ISDN line

With Broadband available across the majority of the UK now, ISDN is no longer offered to residential customers. Existing ISDN lines still work, but new ISDN services aren’t provided to individuals. You can still get a Business ISDN line though. At the time of writing, the cost for an ISDN2e is £199 to have one installed, with line rental about £100 a quarter. For more details on ISDN for Business, go to BT Business ISDN

That’s just for the line, the you’ll need to buy the CODEC (to handle the audio part).

The ISDN Codec

Most commonly, these are single 1 Unit 19″ rackmount devices. We’ve been struggling to find a picture of an audio CODEC that we can use without infringing someone’s copyright, and have managed to find this picture of an ISDN CODEC installed at a radio station one of us used to work for. We think it’s a Glensound ISDN Audio Codec:

ISDN Audio Codec

A rackmount ISDN Audio Codec

One the second-hand market , prices start from around £1000. Take a look at for new and used ISDN equipment. Now and again, a few bargains pop up on eBay. You do have to be careful in that there are different formats of audio codecs out there, and you need to ensure that any ISDN audio codec you buy will be compatible with the system in use by your potential employer.

The Alternative to ISDN?

As you can see, these days, getting ISDN isn’t cheap. So, what’s the modern alternative?

Well, as far as we know, there isn’t really a viable alternative. The likes of Skype allow chat over the Internet, but the quality is way too low. There are a few voice-over-Internet services that offer higher bandwidth, but none that have really taken off.

The cheaper alternative, is for the voiceover to record the audio locally, then get it to the recording studio using file transfer (or CD and Royal Mail). It’s still possible for the producer to “produce” – they use a standard phone line, and listen to the voiceover down the phone as it’s being recorded, and when they’re happy, the voiceover sends the appropriate ‘take’.

To do this, the voiceover would record the session in something like Audition or Audacity, then upload the finished high quality WAV to some hosted webspace on the Internet using FTP software. WAV files are too large to email, and MP3 files normally too low quality for broadcast, due to compression. If anyone’s interested in us writing a “how-to” guide on this, please add a comment below, and we’ll see what we can do!


Comments? Or voiceover hints and tips? Please add them below

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