Traditionally, the industry standard for remote recording of broadcast quality audio has been the tried and tested ISDN unit, a clunky, expensive piece of boxed hardware, requiring an ISDN network for delivery.
In the broadband era, ISDN networks start to look like ancient and expensive technology. ISDN has survived in many radio stations and post production studios on the back of a strong legacy, but it’s not a practical option for the jobbing producer.