Studio Technologies 47A - Manual (Page 13)

Model 47A User Guide Issue 1, September 2014
Studio Technologies, Inc. Page 13
The most direct method is to prepare the
female XLR mating connectors so that
common is on pin 1, power is on pin 2,
and audio is on pin 3. With this connection
scenario only audio channel 2 (the channel
associated with pin 3 of the Model 47A’s
2-wire PL intercom interface connectors)
will be utilized. Pin 2, the Model 47A’s
audio channel 1, will only be used for con-
necting DC power to the connected single-
channel devices.
In some single-channel PL intercom sys-
tem applications it may be desirable to take
full advantage of the two channels asso-
ciated with each Model 47A interface. In
these applications one might want to view
the Model 47A as providing four 2-wire-to-
4-wire interface circuits. The Model 47A can
certainly be used in this fashion, but adapt-
er cables will have to be prepared. Refer to
Figure 2 for details.
These adapters will “split” the Model 47A’s
2-wire PL intercom connectors into two
3-pin male XLR connectors, one for each
audio channel. Pin 1 of the female 3-pin
XLR intended to mate with the Model 47A
will connect to pin 1 of both 3-pin male
XLR connectors. Pin 2 of the female XLR
will go to pin 3 of the male XLR designated
as channel 1. Pin 3 of the female XLR will
go to pin 3 of the male XLR designated as
channel 2.
Using two adapter cables the Model 47A
can be directly interconnected with four
Clear-Com intercom circuits. However,
power for the connected devices must be
provided by external power sources. The
Model 47A’s ability to supply intercom
power will not be utilized.
Note: It’s critical that the correct configu-
ration settings be made when using the
Model 47A’s interfaces to support four
independent intercom circuits. Specifically,
the 2-wire power source configuration DIP
switches must be set for external. In addi-
tion, the auto terminate DIP switch must be
placed in its on (up) position. Refer to the
Configuration and Advanced Configuration
sections of this user guide for details.
Remote Control Inputs
The Model 47A allows connection of three
externally provided DC signals. These sig-
nals can provide remote control operation
of three functions: auto nulling for interface
1, auto nulling for interface 2, and a special
“mic kill” function. Remote control of the
auto nulling functions provides a resource
identical to that of the front-panel pushbut-
ton switches. The exact manner in which
the buttons and the remote control inputs
operate depends on the setting of the auto
null button configuration DIP switch. The
“mic kill” function is unique, only being
available using the remote control input. It
causes a 500 millisecond “burst” of 24 kHz
signal to be sent sequentially to both of the
2-wire partly-line interface channels associ-
ated with each of the Model 47A’s two in-
terfaces. To clarify, a “mic kill” signal is sent
to a total of four intercom channels when-
ever the function is activated. Independent
control of sending “mic kill” signals to
interface 1 or interface 2 is not supported.
Figure 2. Adapter cable wiring diagram