Sidetone Adjustment; Alternate Powering Methods; Method One: One Channel Operation With A Non-Rts Power Supply - RTS BP325 User Manual

7 Connections And Operation
f. Setting DIP switch 3 to the ON position will dis-
able the channel 2 TALK button. Setting DIP
switch 4 to the ON position will disable the chan-
nel 1 TALK button.
g. As supplied, the BP-325 can generate an inaudible
talk-off signal which can be used to deactivate the
talk buttons on other intercom stations connected
to an intercom channel. To turn this feature OFF,
set DIP switch 6 to the OFF position.
h. As supplied, other intercom stations can deactivate
the TALK buttons on the BP-325 using the Talk-
Off feature from their intercom stations. To disable
this feature, set DIP switch 8 in the OFF position.
i. Using the LINE LOOP connector for an external
mic ON/OFF switch:
1. Unplug the LINE LOOP connector from J6 on
the circuit board, and plug it into J4.
2. Connect the external mic switch to the LINE
LOOP connector using an SLR-3-32 female recep-
tacle wired as follows:
Pin 1: Remote Mic Switch Common
Pin 2: No Connection
Remote Mic Switch 
Pin 3:
Normal-open Contact
3. To use the external mic switch, first set one or
both TALK buttons to the latched-ON position.
Then, press the external mic switch to turn ON the
TALK button(s). Release the mic switch to turn off
the TALK button(s). Note, the TALK buttons may
still be turned ON or OFF from the BP-325; how-
ever, the external mic switch will not work unless
the TALK buttons are first turned on at the BP-
325.

Sidetone Adjustment

You can change the level of your own voice heard in your
headphones while talking on an intercom channel. Adjust R39 to
change your voice level when talking on channel 1. Adjust R52 to
change your voice level when talking on channel 2.

Alternate Powering Methods

General
When using an RTS power supply to power the intercom system,
power is carried to the BP325 on pin 2 of the LINE INPUT
connector along with the channel 1 audio. Pin 1 is the DC return.
The unique design of RTS power supplies permits power to be
carried on an audio channel. RTS power supplies also provide the
proper terminating impedance for each intercom channel. If a non-
RTS power supply is used, there are two alternatives for connecting
power and intercom audio.
The first method uses channel 1 only to connect the non-RTS power
supply. Audio on channel 1 will be unusable as the power supply
will look like a short circuit at audio frequencies. Channel 2,
however, will still be operational. Also, channel 2 will require a
terminating impedance, since this is not supplied by the non-RTS
power supply.
The second method allows the use of a non-RTS power supply
while still maintaining two audio channels. This method requires an
additional wire to the belt pack, and the LINE LOOP connector will
not be usable for connecting another intercom station. Also, each
intercom channel must be properly terminated. The two methods are
discussed below.
Method One: One Channel Operation With A Non-RTS
Power Supply
Using an XLR-3-32 female connector, connect the external power
source and the channel terminating components to the LINE INPUT
connector as 
shown in Figure 2.
If desired, the LINE LOOP connector may be 
used to connect power and audio to an additional 
intercom station.
Pin 3, Ch 2 +Audio
Pin 2, +18 TO +24 VDC
TO BP325
LINE INPUT
Pin 1, Common
LINE INPUT Connector Wiring for 1-Channel
FIGURE 1.
Operation with Non-RTS Power Supply
CUT
TRACE
Bottom View of the Main Circuit Board
FIGURE 2.
BP-325
200 Ohms TO INTERCOM
CHANNELS AND
POWER SUPPLY
+
10mF / 50V