Introduction
Sonifex HY-03 User Handbook
1
Introduction
The HY-03 is a high quality analogue telephone hybrid, which is suitable for most general telephony applications and is
often used in radio and TV stations, bingo halls and dealing floors. The analogue HY-03 telephone hybrid is the
replacement for the HY-02, which for many years has set the standard as an excellent value, high quality telephone
hybrid.
The HY-03 can be used for any application where a clean telephone signal is required and the line is not subject to delay.
The HY-03 retains many of the features of the HY-02 and adds some additional ones. Some of the features of the HY-03
include:
• Fully automatic – adapts to varying line conditions and has automatic signal limiting.
• Local and remote line hold switching – calls can be remotely switched through a mixing console.
• Momentary or permanent latching remotes can be enabled.
• Balanced mic/line input – 10k
Ω
balanced input selectable for 0dBu clean feed line, or microphone level with adjustable
gain.
• Balanced output – 0dBu low impedance balanced output, with output gain adjustment.
• Mixed output – the output can be a mix of the caller and mic/line input signals for recording both sides of the
telephone conversation.
• Integrated ring detector – automatic call answering after a pre-determined number of rings.
• Fitted with K-break disconnect (line polarity reversal in the US) detection as standard with an option for dial-tone
disconnect (HY-03DTD option).
• Line limiter, bandpass filter and output noise gate with preset threshold providing low distortion crystal clear audio.
• 45dB typical line balance rejection on tone, 28dB on complex waveforms.
• Built in power supply with switchable 115V, or 230V, mains input.
• BABT approval compliant with European PTT specifications.
What is a Telephone Hybrid ?
Telephone hybrids (or telephone balance units, TBUs) provide the interface between professional audio equipment and the
public telephone network. They provide protection for your equipment and the public telephone lines, allowing for varying
line signals and line conditions. Automatically canceling out the unwanted signal they also facilitate two-way
communication down a single telephone line, converting the two-wire telephone signal to a four-wire send and return
signal to be linked to a studio mixer, for example.
The hybrid has a telephone line connection and separate terminals for audio input and output from a broadcast mixer, or
other professional audio source.
A large proportion of Sonifex hybrids are used in radio and television broadcasting applications for allowing external callers
to be connected to the studio mixing console. Most of the other units are supplied to communication operations for
allowing extremely effective conversion between four-wire audio circuits and standard telephone lines.
Built to a very high specification, the HY-03 is simple to install and automatically adapts to line conditions and programme
content.
Integrated Ringing Detector
Ringing detectors can be used when you need to answer a call automatically, for instance, if a journalist files a report to a
tape recorder over a telephone line, the call can be picked up after a set number of rings by the ringing detector. The HY-
03 has a built in ring detector that is enabled by one of the configuration settings switches on the rear panel.
Available Formats
The HY-03 analogue telephone hybrids are available in three different formats, each with its own approved, internal power
supply :
HY-03 & HY-03 US
Automatic analogue TBU with ringing detector, free standing
Figure 1-1 : HY-03 & HY-03 US Front & Rear
Disconnect the mains supply before removing the equipment covers.
HANDSET
REN = 1
LINE
MIC/LINE
INPUT
This product must be earthed
REMOTES
SETTINGS
PERMANENT
MOMENTARY
OUTPUT
115V - 230V
MIC
LINE
MIC
LEVEL
OUTPUT
LEVEL
