BDM 400 Microphones
Operating Instructions
6
BDM400 Operation Manual issue 10
2.2 H
ARDWARE
S
WITCHES
AND
S
ETTINGS
Depending on model, there are up to 6 settings that are available
by removing the right hand side panel of the microphone. These
are shown in Figure 2.2.
Figure 2.2 — Hardware Settings (BDM401 shown)
Ident Marked As... Function
A
STD / MON
BDM401 (and Processor Bypass All Call) only - see notes below
Fit link in "STD" position if Monitoring of the Access Line is NOT
required when in "Parallel" mode *
Fit link in "MON" position if Monitoring of the Access Line IS
required when in "Parallel" mode
B
S / P
BDM401 only - see notes below
Fit link in "P" position to use Parallel Communications *
Fit link in "S" position to use Serial RS485 Communications
C
Gain / Limiter SW1.1 - Set to ON to increase the gain by 15dB
SW1.2 - Set to "ON" to enable the limiter
D
SURV Level
Sets the 20KHz surveillance level used to monitor the microphone
capsule
E
O/P Level
Sets the Output level
F
IND Level
Sets the Indicator sensitivity (factory preset)
G
LK3
Make link if a "Bypass" switch is fitted
H
LK2
Make link to connect spare RJ45 conductor to +V IN.
This may be useful in installations with long cable runs.
Can only be used if Bypass switch is not fitted.
N
OTE
: Monitoring of the Access Line is applicable to the BDM401 when
it is set to "Parallel" Mode or multi-zone BDM microphones with a
Bypass "All Call" switch fitted. Monitoring is acheived by placing a
Zener Diode between the Access Line and 0V.
N
OTE
: * The Factory Default setting for BDM401 is "P" position for
"Parallel" operation.
