Telos One Hybrid
Danny Hosford
In the mid-1980s, Telos pioneered the very first digital adaptive telephone hybrid. Since then, their POTS phone hybrids have earned a worldwide reputation to deliver clean, clear caller audio from even the most difficult calls. The new Telos Hx2 represents the highest state-of-the-art in hybrid performance, with Telos processing technologies that take the POTS hybrid to a new level of consistently superior performance, regardless of telephone line characteristics.
The Telos Hx2 represents the highest state-of-the-art in hybrid performance, with Telos processing technologies that take the POTS hybrid to a new level of consistently superior performance, regardless of telephone line characteristics.
Inside the dual-hybrid Hx2, you'll find advanced hybrid technology with new features that significantly sweeten and control caller audio. It comes standard with Auto-Answer, caller disconnect detection, sophisticated new audio-leveling and anti-feedback routines for enhanced open-speaker applications, call screening and line-hold features, front-panel send and receive audio metering, plus much more. This version offers AES3 I/O.
In the mid-1980s, Telos pioneered the very first digital adaptive telephone hybrid. Since then, our POTS phone hybrids have earned a worldwide reputation for extracting clean, clear caller audio from even the most difficult calls.
Hx1 and Hx2 are probably the most fully-featured POTS hybrids ever created, with Auto-Answer, caller disconnect detection, audio-leveling and anti-feedback routines for open-speaker applications, call screening and line-hold features, and much, much more. Audio processing tools include a new symmetrical wide-range AGC and noise gate by Omnia, with adjustable gain settings to help keep caller audio smooth and consistent from call to call. Adjustable caller override improves performance even further, and allows you to individualize the degree to which the announcer ducks the caller audio. Finally, our famous Digital Dynamic EQ, coupled with an adjustable smart leveler, keeps audio spectrally consistent from call to call.
Telos Hx2 two-line POTS telephone hybrids are the most advanced hybrids ever developed for use with analog phone lines. Hx hybrids contain advanced 3rd-generation Telos hybrids for superior audio quality; universal POTS interface features disconnect-signal detection, which works with Telco providers worldwide. Hx hybrids include unique features to make operators' lives easier, such as Auto-Answer with selectable ring count, a switchable mic/line input, call screening and line-hold features, and front-panel send and receive audio metering. Audio sweetening tools include Telos Digital Dynamic EQ (DDEQ) and adjustable smart leveler, symmetrical wide-range AGC and noise gating by Omnia, studio adaption and pitch shifter for use in open-speaker application, and adjustable caller override.
Take total control of your talk shows and call-in segments
In the mid-1980's, Telos pioneered the very first digital adaptive telephone hybrid. Since then, their POTS phone hybrids have earned a worldwide reputation for extracting clean, clear caller audio from even the most difficult calls.
Telos has contributed plenty of improvements to POTS hybrid technology in the past 20 years, and the Hx1 and Hx2 represent the highest state-of-the-art in hybrid performance. Advances in DSP have been pretty great as well. They've used every bit of knowledge gained to make Hx1 and Hx2 the best, most advance POTS hybrids we've ever made, without much doubt.
Inside the single-hybrid Hx1 and dual-hybrid Hx2, you'll find Telos processing technologies that take the POTS hybrid to a new level of consistently superior performance, regardless of telephone line characteristics. This advanced hybrid technology brings new standard features that sweeten and control caller audio better than ever before; features you won't find in other POTS hybrids.
On the front panel, you'll find EQ Meters for each hybrid, to tell you exactly how much DDEQ is being applied. Next to those, separate Send and Receive level meters monitor each hybrid. There's also an animated line status display that visually indicates when a line is ringing in, on air, on hold or available. A complement of Take, Hold and Drop buttons complete the front-panel control set.
Around back, you'll find a switchable mic/line input, balanced analog receive-out output, RJ ports for telco input and phoneset, input level adjustment, and a DB9 remote control connector with GPIO closures for hybrid control and status indicator lamps. Need digital I/O? No problem - Hx comes in an AES/EBU version with built-in sample-rate converter.
Hx1 and Hx2 are probably the most fully-featured POTS hybrids ever created, with Auto-Answer, caller disconnect detection, audio-leveling and anti-feedback routines for open-speaker applications, call screening and line-hold features, and much, much more. Audio processing tools include a new symmetrical wide-range AGC and noise gate by Omnia, with adjustable gain settings to help keep caller audio smooth and consistent from call to call. Adjustable caller override improves performance even further, and allows you to individualize the degree to which the announcer ducks the caller audio. Finally, the famous Digital Dynamic EQ, coupled with an adjustable smart leveler, keeps audio spectrally consistent from call to call.
This compact, modem-case device presents superb digital telephone hybrid performance for broadcast, teleconferencing, and communications applications. Proven Telos processing technologies perform all hybrid functions, gain control, and filtering completely in the digital domain. The use of intelligent software, rather than complex hardware, makes the Telos ONE very affordable while ensuring consistently superior performance regardless of telephone line characteristics.
Throughout history, POTS technology has presented a special challenge to the average broadcast engineer. A POTS phone line consists of a single twisted pair of wires which carry all of the signaling voltages as well as both of the callers' voices. In a broadcast situation, if the audio on the phone line were placed on the air unaltered, there would be two instances of the host's voice reaching the console: One instance from the microphone in the studio and the other instance from the phone line itself. This creates echoes and comb-filtering as the two instances are mixed together at the console. Herein lies the problem.
The solution to this problem is a hybrid. In a general sense, a hybrid is a device that takes the input signal and applies it to the phone line out of phase and time-aligned. This nulls the undesired audio from the phone line and leaves only the desired audio. This sounds like a simple task, but there are many factors at hand that make doing this a challenge.
Originally, transformers were used in a hybrid configuration with an extra winding that could be configured out of phase. This is called a passive hybrid and only guarantees a few dB of isolation. Digital Signal Processing eventually arrived on the scene making active hybrids, like the ones from Telos, possible.
In the real world, the phone line is not purely resistive, but a rather complex impedance, causing amplitudes of certain frequencies to vary. Passive, transformer-based hybrids are not capable of automatically matching the impedance, capacitance, or reactance of the phone line. Digital Signal Processing eventually arrived on the scene making active hybrids possible. Active hybrids like those made by Telos have dynamic matching circuits to help with this, allowing up to 30dB of attenuation to the undesired signal.
The cancellation of an undesired signal is sometimes called "nulling." The Telos hybrid sets the timing and phase of the null signal by emitting a burst of noise down the line to coarse align its timing circuits. The null algorithm automatically continues to make fine adjustments throughout the course of the call to improve the amount of rejection.
The amount of rejection of the unwanted signal is sometimes called Trans-Hybrid Loss and there are a number of factors that can reduce this in a system. Only when the impedance of the hybrid is the same as the phone line, and the out-of-phase signal is matched to the original in both amplitude and phase, will full cancellation of the send signal be achieved.
When a phone line has a linear response like the example on the left or a smooth response like the example in the middle, impedance can be easily matched by the active hybrid system. Responses like the one on the right present more of a challenge and may not perform as well.
Another factor presented in today's mixed world of analog and digital telephony is drifting of the time-base on the phone line. Today, many of the POTS lines provided are not analog at their origin. Instead, they are digital (commonly SIP or VoIP) connections converted to analog POTS by some kind of device, be it a central office switching system or a locally installed ATA or similar device. These devices can often use buffering on the digital connection. Buffering did not exist in the POTS world and is fine as long as the amount of time that the buffer delays is consistent throughout the call.
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