D&R TelCom User Manual

TelCom

USER

MANUAL

Version1.02

Manual page 1

Dear Customer,

Thank you for choosing the TelCom Telephone Hybrid.

This time you are not faced with a huge manual because it is simply not necessary because of
the natural recognition of all functions on the user interface.
All functions are self-explanatory and you will certainly appreciate the ergonomics of this
design.

We are confident that you will be using the TelCom for many years to come, and wish you a
lot of success in your application.

With kind regards,

Duco de Rijk
President

D&R ELECTRONICA WEESP B.V.

Rijnkade 15B
1382 GS WEESP-HOLLAND
The Netherlands
Phone: [phone]
Fax: [phone]
Website: http://www.d-r.nl
E-mail: [e-mail]

Manual page 2

What is a Telephone hybrid?

Telephone hybrids 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.

Each hybrid has a telephone line connection, a handset connection and separate connectors
for audio input and output from a broadcast mixer, or other professional audio source.

A large proportion of D&R hybrids are used in radio and television broadcasting applications
allowing external callers to be connected to the studio mixing console. Most of the other units
are supplied to communication operations allowing extremely effective conversion between 4­wire audio circuits and standard telephone lines.

Specs:
AUDIO PROGRAM IN AND OUT

Connectors : Jack stereo 6.3mm and Cinch connectors
Input impedance : 5kOhm (transformer balanced)
Output level : -40 up to +6 dBu
Output impedance : 2kOhm (transformer balanced)
Noise on Receive output : less than -82dB (A weighted)

GENERAL DATA

Power supply : Powered by telephone line
Dimensions : Front 240x44mm, Depth 110mm
Weight : 725grams

LINE INTERFACE

Connector : RJ11
Nominal input level : -6dBu
Nominal output level : -6dBu
Compensation Mode : fully electronic*
Impedance : 600 Ohm

* Depends on telephone line characteristics

Manual page 3

Front panel lay-out

Hook

Call LED When a call is coming in this LED lights up indicating a call is coming in.

Ringer off

Send

Receive

Side tone With this trimmer you can adjust the side tone to a minimum

Line connect switch to connect and disconnect calls from the telephone line.
At the same time a LED lights up

This hidden switch allows you to turn the internal buzzer off by inserting a
small screwdriver

This trimmer adjust the level of the audio sent to the telephone caller which
is connected to the SEND jack/cinch connector on the rear panel.

This trimmer adjust the level of the audio coming in from the telephone
caller which is connected to the RECEIVE jack/cinch connector on the rear
panel.

Manual page 4

Back panel lay-out

RECEIVE

SEND

PHONE: RJ-11 connector to connect with a telephone set.

LINE (wall) RJ-11 connector to connect with the public telephone network.

USER MANUAL

The D&R TelCom telephone Hybrid is designed to create an easy connection between the
public telephone line and your studio equipment.
The Hybrid has to be inserted between your telephone and the telephone line.
Connect the two wires of the telephone line’s wall unit to the RJ-11 connector labeled
LINE (wall) and connect the telephone appliance itself to the Hybrid’s phone output on the
RJ-11 connector labeled PHONE. This can be done with standard available cable assemblies
from your local phone shop.

Now the hybrid is interfaced (fully balanced) between your telephone appliance and its
connection to the outside world. The hybrid can now split the send and return signals.

Now connect the hybrid’s balanced audio output labeled RECEIVE to a (preferable) balanced
input of around +4dBu.
The TelCom stereo jack or Cinch connector labeled SEND has to be connected to a line level
(cleanfeed) output of your mixing console.
This output has to be the mix of all signals except the signal coming from the hybrid itself to
avoid feedback. An Aux output will do, or in broadcast mixers a clean-feed is the best.

NOTE: The output of the Hybrid can be connected balanced via the jack connector or
unbalanced via the Cinch connectors.

(Please be aware that the jack interrupts the Cinch connection)

Balanced Stereo
a mixer.

Balanced Stereo jack/Cinch input to be connected to Mix
Minus/Clean feed (N-1) or Aux output of the mixer.

jack/Cinch output to be connected to line input of

Manual page 5

WIRING SCHEME

PHONE: RJ-11 connector to connect with a handset.

LINE (wall) RJ-11 connector to connect with the public telephone network.

SEND

RECEIVE

CONNECTION WIRING OF BOTH PHONE AND LINE RJ-11 CONNECTORS

PHONE/WALL RJ-11 FUNCTION CONNECTION

Pin 1 n.c.

Pin 2 A (telephone line) In/out

Pin 3 B (telephone line) In/out

Pin 4 n.c.

Balanced Stereo jack or unbalanced input to be connected to Mix
Minus/Clean feed (N-1) or Aux output of the mixer.

Balanced Stereo jack or unbalanced Cinch output to be connected to
a line level input of the mixer.

WIRING OF AUDIO IN AND OUTPUTS

STEREO JACK TO LINE
INPUT / TO CLEANFEED
OUTPUT

Screen Screen (ground) Audio ground

Ring Non-phase (cold) Audio -

Tip Phase (hot) Audio +

MONO CINCH TO LINE
INPUT / TO CLEANFEED
OUTPUT

Screen Non-phase (cold)/ground Audio - ground

Tip Phase (hot) Audio +

SPECIFICATIONS

Audio Inputs

RECEIVE

Impedance 5k Ohm, electronically balanced

Common mode rejection >20dB

Maximum input level +6dBu

Nominal input level -6 dBu

Frequency response 300Hz – 5kHz

Connectors balanced-STEREO JACK / CINCH

TYPE CONNECTION

Manual page 6