Telos NX12 User Manual

Page 12

2 | section 1

Conference linking lets you set up high-quality conferencing between callers with no

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external equipment needed.
Caller ID support on both ISDN and POTS lines.

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The Nx12 can serve two studios, each with two hybrids.

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In the two-studio modes, lines can either be shared or exclusive to each studio. In the latter

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case, there is no possibility for accidental interaction.
Support for up to eight Desktop Directors.

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Compatibility with Telos Assistant Producer and third-party call control software applica-

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tions.

Why ISDN Makes Sense for Broadcast Talk Show Systems

The Nx12 works with either traditional analog Telco lines or with ISDN (Integrated Services

Digital Network). We recommend ISDN service for telephone connections whenever possible.

Contrary to the perceptions of some, ISDN is widely available, cost-effective, and offers many

advantages for studio on-air telephone systems. It is yet another example of digital technology

enhancing broadcast operations. There is no comparable technology for getting audio to and

from the public telephone network. Even compared to VoIP, ISDN is superior, with its lower

delay and higher Quality of Service.
To assist you to have a smooth, troublefree installation, we provide plenty of advice right here

in this manual, and live support by people with years of ISDN experience. (Many thousands of

Telos ISDN interfaces and Zephyrs are deployed around the world!)
Currently, the dial-up telephone network is nearly entirely digital. Only the “last mile” copper

connections from the telephone Central Office exchange to the customer’s site remain with the

archaic (more than a hundred years old…) analog scheme. ISDN offers us a way to link our

studios directly into the Telco digital infrastructure without the usual impairments of analog

connections.
In all-digital studio facilities, the telephone interface can maintain a digital path all the way

using either AES or Livewire networked audio on the studio side
While the application of digital signal processing to the problem of separating announcer

and caller audio – pioneered by Telos and used in all of our telephone interfaces – has made

a dramatic improvement over analog-only hybrids, using digital phone lines for on-air calls

further improves performance for several reasons:

Exceptional send-to-receive isolation.

Traditional analog phone lines multiplex both

speech directions in order to use a single pair of wires for a conversation. This causes what’s

referred to as ‘leakage’ – when the announcer’s audio is present on the hybrid output,

creating an annoying ‘hollow’ or ‘tinny’ sound. Telos digital adaptive hybrids reduce this

problem. But ISDN offers independent and separated signal paths, so our hybrids only have

to operate on the far-end analog line, if any. The result is much lower leakage.
Higher send levels

. We don’t have to be concerned about regulations designed to prevent

crosstalk on analog lines, so we can increase send-to-caller levels.
Lower distortion

. The analog-digital conversion chips used in telephone central offices

are poor compared to the converters used in professional audio equipment. Fidelity is not

an important consideration when telephone equipment designers choose parts for this

function. In a professional interface for studio applications, we can afford to design-in much

better converters. Noise-shaping functions permit a larger word-length converter to provide