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62. Let’s Review   4/16/15  by Dave Immer

It’s time for an overview of where we stand with how ISDN and IP enables live audio networking. These days you can’t really discuss ISDN without including the internet, or IP. Both are digital networks and both can deliver the same data. The difference is ISDN connections are circuit-switched 64kbs channels and IP connections are packet-switched with optional average bit-rates. ISDN connections are a fixed, guaranteed speed, private and exclusive. Broadband IP connections have fluctuating conditions and share a common public network.

The ISDN specification guarantees a rock-solid bit-rate making it perfectly suited for live production audio. The internet is always presenting jitter, dropped packets and fluctuating bit-rates, particularly problematic for marginal-speed connections. But the disadvantages of IP are being overcome by improved up/download speeds and new audio coding algorithms.

ISDN persists as a known quantity to many users who are comfortable with the technology and the popular hardware. It is ISDN’s steady, reliable 64kbs channels that are it’s great strength. And there are audio production studios who, as a matter of policy, will only accept ISDN connections and not IP. But one should avail themselves of the right tool for the job and have the ability to use IP when appropriate. ISDN (when available) remains the best choice for live audio networking.

Ultimately it’s compatibility with the far-end that determines what network and what codec you use. If required, a bridging service can connect you to anything.

Let me know if you have comments.

-Dave