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Issue 3

3.

Limiter

Selecting the limiter will ensure that the signal level remains fairly constant irrespective of input level changes.
Using it will prevent system overload when different personnel use the microphone or speak too close to the
microphone.

Technical Specification

MICROPHONE

LINE

Nominal output level

2.5mV

250mV

Maximum output level limiter operating

7mV

700mV

Output impedance

47ohms

400ohms

Frequency Response

       200Hz - 10KHz

Power Requirements

24V DC

26mA  Standby

100mA Max

The cable is terminated to a 25 way ‘D’ connector.  It is supplied with a BMS25 single gang socket box and
connections are made using screw terminals

FUNCTION

   CABLE COLOUR

BMS 25 CONNECTIONS

ZONE   1

NPN open collector outputs 40V @

Green

       1

  2

100mA Max. to zone select relays

Grey

       2

  3

etc.  Connects to 0V when the zone

Pink

       3

  4

and speak keys are selected together.

Orange

       4

AUDIO - Output floating

Brown

     16

CABLE SCREEN - Connect to 0V

     17

AUDIO - Output floating

Blue

     18

0V

Black

     19

24V DC - Supply input

Red

     20

ACCESS - Amplifier -

White

     21

connects to 0V when speak or All Call keys are pressed.  24V @ 30mA

BUSY Indicator - Switch to 0V to illuminate

Mauve

     22

1. Remove 2 screws

2. Lift top
at rear

3. Slide top forward
and off base

98
m

m

65mm

4mm fixings

FIG 2a - BDM 204 - Wall Mounting Dimensions

FIG 2b - BDM 204 - To remove the base

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