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3 Connecting the DHY-04G/HD TBU
34dB under no signal conditions, eliminating the effects of telephone line
crosstalk.
Isolation of better than 71dB is created between the input and output
connectors when the hybrid unit is functioning on an exchange line.
Using The AES/EBU Input & Output
The unit is also capable of working in the digital domain by supplying AES/
EBU digital audio into the input XLR. The unit will automatically detect
this digital signal and so will change the output to a digital audio signal
synchronised to this input. The unit will treat 0dbFS to be the equivalent
to a +18dbU analogue signal. The AES lock LED will indicate when a valid
AES signal is present. Signals above -6dbFS have AGC applied to limit the
internal signal to a maximum of -6dbFS (equiv +12dbU).
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-04G/HD
Receiving a Call
Incoming calls can be answered manually from the line connect button,
or the remote line connect switch, or automatically by enabling the auto
answer feature (settings SW4 ON), or externally via the serial or Ethernet
ports. Incoming calls simulate ringing by cadence illumination of the line
connect button. The line connect button lamp is off in the non-connected
mode and illuminated in the connected mode.
Note:
The remote line hold ouput mimics the front panel line connect
button lamp, i.e. it flashes when ringing and is on when the line is held.
The hybrid unit now behaves as a 4-wire to 2-wire converter with signal
inputs at the mic/line input connector and telephone caller at the output
connector.
The call may be cleared by re-pressing the line connect button, or by means
of the remote divert switch, or via the serial or Ethernet ports. If the remote
caller hangs up then the call is cleared automatically.
Integrated Ringing Detector – Auto Answer
Ringing detectors can be used when you need to answer a call
automatically, for instance: If a journalist files a report to a recorder over
a telephone line, the call can be picked up after a set number of rings by
the ringing detector. The DHY-04G/HD has a built in ring detector that is
enabled by setting SW4 on the rear panel.
Making a Call
To initiate a call, use the speed dial/ redial buttons on the front panel, or
use the serial port (directly or via SCi) or Ethernet port (directly or via the
webserver) to request a call to a specific number. When the call has been
established, the call will be handed over to the telephone hybrid unit. To
clear the line at the end of the call, press the line connect button. The line
connect button lamp is off in the non-connected mode and illuminated in
the connected mode.
Using Speed Dial Buttons
There are also 4 Speed Dial buttons on the front panel that can make
calls to 7 numbers setup via the webserver. When dialling, the unit shows
the dialling by a rotating illumination pattern on these buttons. Speed
Dials 1-4 are accessed by a simple press on buttons 1-4, Speed Dials 5-7
and last number redial are accessed by pressing and holding buttons 1-4
respectively.
Call Established
Level Setting
The DHY-04G/HD hybrid operation is optimised for signals around 0dB.
The front panel gain switches can adjust the signal levels for both caller
and sender. The default position for these switches is receive gain (upper)
fully counter-clockwise (6dB) and the transmit gain (lower) to be in the
