11
Connecting the DHY-04G/HD TBU 3
3 Connecting the DHY-04G/HD TBU
IEC Mains
Connect the earth and mains power connections as per the information
given in the Configuration & Controls sections of the handbook. The hybrid
unit should be connected with reference to the following diagram.
Figure 3-1: DHY-04G/HD User Connections
GSM Antenna
Connect the GSM antenna to the rear panel and use the signal strength
indicator to position the device/antenna to achieve the strongest signal.
Remote Line Hold
A remote switch may be connected at the Remotes socket in order to
control the line connect button from, say, the telco channel of a mixing
desk.
Connect the output from the mixing desk “clean-feed” to the mic/line input
of the DHY-04G/HD, with the mic/line input select switch set to “Line”. A
clean-feed is a signal produced by a telco module on a mixer which is used
as the output to be fed back to a caller on a telephone line. The cleanfeed
is a sum of all the other signals which constitute the programme output,
except for the caller’s audio (this is so that the caller doesn’t hear him/
herself in the ear-piece). A cleanfeed signal will generally be of a better
quality than a mix-minus signal.
Mic/Line Input
The characteristics of the mic/line input are determined by the state of
the mic/line configuration selection switch. It is a balanced bridging input
and in line mode will accept normal signals at 0dBu peaking to +8dBu
from a sound mixer clean feed. In mic mode the unit will accept 200 Ohm
microphone level signals with a maximum gain of 71dB. It is suitable for a
wide range of microphones and the available gain is 71dB to 29dB, which
can be adjusted by the mic level pre-set mounted on the rear panel and the
front panel ‘Level to Line’ Switch. The input circuitry to the DHY-04G/HD 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.
XLR Output
Connect the output of the DHY-04G/HD to the telco 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
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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 Ohm 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
Microphone
GSM Antenna
Ethernet
Earth
Mains
Power
Remote
Divert
Output
Mic/Line Input
Remotes
GSM Antenna
Earth
Ethernet
Power
DHY-04G/HD
Mixing Desk
Input to
Telephone
Channel
Output from
Mixer
Clean-Feed
