SIP Audio Codecs

Connect between devices with Opus and


Remote Podcast Interview

NAB Show, Las Vegas


ipDTL for Radio Remotes

Capital FM, UK


Townsend Coleman - Voice Actor

In:Quality @ NAB Show, Las Vegas

Radio Days & Media Tours

in a post-ISDN world

Most days, we receive a message along the lines of…

“We have been asked to provide facilities for a book launch, so that the author can perform a day of interviews to radio stations and podcasters.

The stations will need to know the ISDN number in advance, and they will dial in for their scheduled slot.”

This is generally known as an ‘Audio Media Tour’ or ‘Radio Day’.

Stop right there!
– ISDN lines around the world are rapidly being switched off.
SIP is now the standard method of connecting to radio studios.

Planning an Audio Media Tour using SIP

What are the technical requirements on the contributing side?

You will need an IP Codec that supports SIP and the Opus Codec, along with a SIP account.  Another option is to use a computer with a USB microphone and ipDTL.

A hardwired internet connection is strongly advised. Mobile broadband and wifi can give unpredictable results.  Also consider your acoustic environment.  Studio walls are softly furnished for a reason, so avoid bare meeting rooms without carpets or curtains.

Familiarise yourself with the technology, and test everything in advance. Consider your backup plan should a piece of equipment or service fail.

At the Radio Station

When scheduling times with stations, ask which SIP address you should call to connect with them.  SIP codecs are made by various manufacturers, and so the radio producer may know it as a Comrex, Switchblade, Tieline or IPCOM, or they may use ipDTL, which comes with a SIP address.

Sometimes a station may have an IP codec which is not yet set up to use SIP, or they may offer you an IP address. In this instance, you should suggest that they add a SIP account to the configuration.

Old habits die hard, and radio producers – much like parrots – will repeat the old familiar line “What’s your ISDN number?” when prompted.  Their familiar world is being ripped from underneath them, and any mention of IP codecs will likely induce panic.  Please do what you can to help them at this difficult time.

It is not uncommon for a radio producer to tell you that their station doesn’t use SIP, when we know for a fact that they do, because we helped their engineers to set it up.  The BBC, iHeartMedia and countless other large and small broadcasters are all now able to receive SIP calls.  If in doubt, ask us.

Create Shortcuts

In ipDTL or your SIP Codec, create dialing shortcuts to save you from manually entering SIP addresses on the day.  Over time, you’ll build up a handy database, that will make future media tours so much easier.

If you’re using ipDTL, consider a Silver subscription, so that you can connect to the next station while an interview is in progress. Just be sure to first fade down the audio on the second remote channel in ipDTL, so that it doesn’t disturb the current interview.  Then, when the time is up, you can simply fade one down, and the other up, for a swift and seamless changeover.

Send a Link

A neat feature with ipDTL and is the ability to send a link to a radio station or podcaster, which allows them to connect with you using just their web browser on a computer.  They must be sure to send you a mix-minus.

If all else fails, then – for now at least – you may be able to fall back to ISDN.  It’s a tricky old technology, and requires a little knowledge of the various formats and quirks to make it work.  While ipDTL will let you receive an incoming call, by far the easiest way is to dial out to the station.

Talk to Us

We do this stuff every day.  It’s all we do.  We can make it work for you too.