13
Connecting the DHY-04 TBU 3
3 Connecting the DHY-04 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.
Telephone Line
The telephone line socket is connected to the telephone network using
the RJ11 to RJ11 cable provided. An adaptor is provided to connect to a
standard BT socket.
Handset
A simple telephone handset can be used to take and make calls when
plugged into the equipment handset connector. An adapter is provided if
the handset is fitted with a BT plug as standard.
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-04, 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 74dB. It is suitable for a
wide range of microphones and the available gain is 74dB to 40dB, which
can be adjusted by the mic level pre-set mounted on the rear panel. The
input circuitry to the DHY-04 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-04 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 digital hybrid
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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
Figure 3-1: DHY-04 User Connections.
Handset
Microphone
Telephone Line
Ethernet
Earth
Mains
Power
Remote
Divert
Output
Mic/Line Input
Remotes
Handset
Line
EarthEarthEarth
Ethernet
Power
DHY-04
Mixing Desk
Input to
Telephone
Channel
Output from
Mixer
Clean-Feed
