Studio Technologies 46A - Manual (Page 16)

Issue 1, September 2014 Model 46A User Guide
Page 16 Studio Technologies, Inc.
Configuration
For the Model 46A to support the needs
of specific applications a number of op-
erating parameters must be configured.
These include the 2-wire party-line power
source, the nominal 2-wire level, and the
nominal 4-wire level. Three 4-position DIP
switch assemblies are used to establish
the desired configuration. One DIP switch
assembly is associated with interface 1, a
second is associated with interface 2, and
a third associated with advanced operat-
ing features that apply to both interfaces.
Configuration – Interface 1
and 2
The DIP switch assemblies associated
with interface 1 and 2 are accessible on
the Model 46A’s front panel. They provide
identical capability for their respective
interfaces. Refer to Figure 5 for a detailed
view. In this section the four switches as-
sociated with interface 1 will be covered in
detail. This information applies to interface
2 as well. The four switches allow selec-
tion of the 2-wire party-line power source,
the nominal level for the 2-wire party-line
channels, and the nominal level of the
4-wire inputs and outputs.
2-Wire Party-Line Power Source
DIP switch 1 is used to select whether or
not the Model 46A provides DC power to
pin 2 of connectors associated with the
2-wire party-line intercom channels. Two
3-pin male XLR connectors, one located
on the Model 46A’s front panel and one
on the back panel, are used to intercon-
nect the Model 46A with the intercom user
devices. When switch 1 is in its off (down)
position the Model 46A will not provide DC
power. This switch setting is appropriate
when an external intercom power supply
is providing power to the intercom circuit.
In addition to power, it’s expected that the
external power supply will also provide the
required 200 ohm terminating impedance
to both pins 2 and 3.
When switch 1 is in its on (up) position the
Model 46A will provide a 30 volt, 315 mA
maximum source of DC power to pin 2 of
the 2-wire PL intercom connectors. The
Model 46A will also provide 200 ohm termi-
nating impedances for both pin 2 and pin 3
of the party-line connectors. The DC power
and termination capabilities allow direct
powering of 2-channel intercom beltpacks,
such as the RTS BP325. In addition, listen-
only beltpacks, such as the Model 34 from
Studio Technologies, Inc. can be directly
connected. There’s also no problem con-
necting single-channel intercom beltpacks
or user stations.
2-Wire Nominal Audio Level
DIP switch 2 allows adjustment of the nomi-
nal audio level for the two 2-wire party-line
channels associated with interface 1. When
the switch is in its off (down) position the
nominal level is –14 dBu. This level is com-
patible with intercom beltpacks from manu-
facturers such as Clear-Com. When the
Figure 5. Detail of front panel showing four DIP
switches