DHY-03 User Handbook
5
on the rear panel. The input circuitry to the DHY-03 has a very effective limiter, which will
prevent high level overloading problems. Ideally, the maximum input level should not
12dBu. This limiter is used for both line and mic input modes.
Connect the output of the DHY-03 to the tele input of the mixing console. The output
connection will deliver a balanced/floating low impedance signal of 0dBm from the
telephone line. The output of the digital hybrid unit is normally 0dBu from a balanced
source of 50 Ω or less across the useful bandwidth of the equipment. The bandwidth is
restricted by the line conditions between 250 Hz and 4 kHz. The output stage is capable
of driving into 600 Ω loads at up to +8dBu. Termination of the output is not necessary
however and direct connection can be made into the mixer telephone return channel.
The output stage has a 3-way gain switch control, mounted on the front panel (level to
line), which may be set to give 0dB signals at the output. In addition an output noise gate
operates when the telephone signal is below the noise gate threshold control. This noise
gate reduces the output gain by 34dB under no signal conditions eliminating the affects of
telephone line cross talk.
Isolation of better than 75dB is created between the input and output connectors when the
hybrid unit is functioning on an exchange line.
Note: The earth bond at the screw terminal must be connected to a technical earth to
ensure the safe operation of the equipment under all line conditions.
Using the DHY-03
First Use
Before using the DHY-03 you should ensure that it is connected as figure 1-5 and that the
unit is setup for the correct line conditions.
1.
With the unit powered off set the dipswitches of the SETTINGS on the rear panel to
the appropriate country specification (see Table 2-1).
2.
Ensure that dipswitch 8 is also set on and then power up the unit. During the power
up cycle the new country code should be reflected in the top row of LEDs, on the
front panel.
3.
Now return the dipswitches to their default condition – switches 1,2 & 6 on, with
switches 3 & 4 also on if you wish to use automatic call handling. The unit should now
be ready to make & receive calls.
Using the DHY-03 with the Broadcast Bionics PhoneBox
The DHY-03 telephone hybrids can be simply configured to operate with the Avaya
telephone switch used in the Broadcast Bionics PhoneBox system. Follow the procedure
for “First Use“ and in section 1, select Country code number 119 (see page 21). This will
configure the hybrid to operate correctly with the Avaya switch.
Using the DHY-03 with Internal Telephone Exchanges
The DHY-03 can be configured to operate with internal exchanges, such as the Avaya
exchange - contact [email protected] with details of the exchange and we
should be able to program the unit to those particular settings, using one of the User Set
country codes (see page 19). Typically, most modern exchanges connect to the outside
INTR
ODUC
TION
INTRODUCTION
1
