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Symetrix T1-101 active telephone coupler



The Radio Systems TI-101 Telephone Interface is the most practical and
economical device on the market today, designed specifically for the
connection of professional audio equipment to telephone lines in
broadcast and production operations. The TI-101 employs a carefully
engineered electronic hybrid circuit which creates a maximum
trans-hybrid loss, yielding effective isolation between the studio's
send to the telephone line and caller return feed. The net result is
clear, intelligible telephone audio fully compatible with today's high
quality broadcast and studio systems.



The TI-101 provides you with not just some, but all of the features
you need in a telephone interface. At the same time, the unit is
simple to connect, simple to adjust, and simple to operate. An output
buss or mix minus feed from the console connects to the TI-101 and
sends studio signal down the telephone line. The TI-101 allows
optimization of the send level for maximum intelligibility. At the
same time, the unit's built-in send limiter can be adjusted to prevent
overdrive of the telephone line. This effectively confines the return
signal from the TI-101 to the console to just the caller's voice. The
DJ or host voice has been effectively nulled out, eliminating any
potential feedback or echo.



Impedance and level matching to and from the telephone line and
console are optimized to preferred levels by the TI-101. In addition,
the caller's voice can be monitored on the studio monitor speakers
without feedback. There is no need for the operator to wear
headphones.



One of the most important features of the TI-101 is that it is a true
hybrid. This means that there is no objectionable gating as in
"speaker phone" type phone boxes. You get natural, two-way
conversation between host and caller.



Specifications

Input impedance 16.7 K ohms (electronically balanced)

Telephone port impedance 600 ohms (transformer balanced)

Nominal input and output

level ranges Back panel switchable between -10 dBm and +8 dBm

Maximum output level +20 dBM

Maximum input level +21 dBm

Typical THD 0.1%

Controls Send level, send limit, receive level,receive
compress/expand,400 Hz and 2.5 kHz equalization, conference link,
coarse, low frequency, and high frequency null adjust

Visual Indicators LED's for indication of send clip, send limit,
receive clip, receive compress/expand, receive mute, and power on

Frequency response (measured from telephone port to output port) 300
Hz to 3 kHz +/-3dB

Typical trans-hybrid loss 20 dB over the specified frequency band
width

Connectors 3 pin "XLR" type for input and output ports, dual banana
posts for telephone tip and ring, 1/4" phone

jack for external mute and conference interconnect cables

Physical size 1 3/4" high, 19" wide, 6" deep (4.45 x 48.3 x 15.2 cm.)

Shipping weight 7 lbs. (15.4 kg)

Power requirements 60 Hz, 120 VAC standard, 50 Hz 220 VAC, upon
request

Construction Aluminum front panel, plated steel chassis, all
connectors pc mounted for maximum reliability