Baldwin Boxall BT10 User manual

Baldwin Boxall Communications Ltd.
Wealden Industrial Estate, Farningham Road
Crowborough, East Sussex, TN6 2JR
Telephone: [phone] Fax: [phone]
Website: www.baldwinboxall.co.uk
Email: [e-mail]
IBT10
Issue 3 Ecr1264
05/11/2001
BT10
Operating Instructions

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Issue 1
BT10 INSTRUCTIONS
The BT10 is a universal interface module.
Connect the input of the BT10 to either a 100 Volt loudpseaker line or the line level output from a
telephone switch. The output at either microphone or line level can be fed into an amplifier.
When a signal of a sufficient level is received at the input, the Vox circuit will operate and it will be passed
via the output into the amplifier. In addition, the unit has a switched 0V available on the ACC terminal to
access the amplifier.
E.G. When using one of our amplifiers, take a connecting wire from the ACC terminal to pin 5 on the
appropriate input socket.
The Vox circuit is designed to ensure that there will not be any unwanted noise appearing at the amplifier
input and being relayed through the loudspeakers.
A pre-set control allows adjustment of the Vox sensitivity. To set it, adjust the control so that it only
switches on when a suitable signal level is present. The TEST LED will illuminate when the Vox has
operated and the access will be switched ON.
The gain preset adjusts the gain of the unit and is factory pre-set at x 2 ( 6 dB). It can be used to
compensate for different input signal levels.
The unit is powered from either mains or 24 VDC. If both are connected, in the event of mains failure there
will be automatic switch over to the 24VDC and the unit will continue to operate.
SPECIFICATION
N.B. All figures are for 1 KHz input signal and gain set at X2 (6dB).
Vox Sensitivity.
Min 2.5mV (-50dB)
Max 250mV (-10dB)
Max output. (Before clipping) 3.0V (11.5dB)
T.H.D. (At max. output) <0.02%
Gain Variable 0 - 16dB (X1 - X6) (Factory set to x2 (6dB)
Input for 0dB output. (At max gain) 128mV (-15dB)
100V line input for 0dB output. 50V
DC supply current at 24VDC <20mA

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Issue 1
LINE
INPUT
ISOLATION
TRANSFORMER
ADJUSTABLE
GAIN AMPLIFIER GATE
ISOLATION
TRANSFORMER
OUTPUT
LINE
100V
LINE
CIRCIUT
ATTENUATION ATTENUATION
MIC
OUTPUT
ACCESS
SWITCHED
ACCESS OUTPUT
RECTIFICATION &
LEVEL SHIFTING
VOX AMPLIFIER
PSU
SUPPLY
24V DC
230V AC
INDICATION
SENSITIVITY
AMPLIFIER
Figure 2 - BT10 Functional Block Diagram
MIC OUTPUT
LINE OUTPUT
LINE INPUT
100V LINE INPUT
VOX SENSITIVITY
GAIN
EARTH
ACCESS
BATTERY +
BATTERY -
20V INPUT
20V INPUT
Fi
g
ure 1 - BT10 PC Board La
y
out
MINMAX
MIN
MAX