Studio Technologies 47A - Manual (Page 17)

Model 47A User Guide Issue 1, September 2014
Studio Technologies, Inc. Page 17
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
nominal audio level for the two 2-wire
party-line channels associated with inter-
face 1. When the DIP switch is in its off
(down) position the nominal level is
–14 dBu. This level is compatible with
intercom beltpacks from manufacturers
such as Clear-Com. When the DIP switch
is in its on (up) position the nominal level
is –10 dBu. This setting is appropriate
when beltpacks from RTS, such as the
BP325, or listen-only talent amplifier units
from Studio Technologies, Inc. are con-
nected. For best Model 47A performance
it’s important that the 2-wire nominal level
selection be made correctly.
4-Wire Nominal Audio Level
DIP switches 3 and 4 are used to config-
ure the nominal level of the input and out-
put circuitry associated with interface 1’s
two 4-wire input and output connections.
Four level settings are available: 0, +4,
+6, and +8 dBu. Prior to setting these
DIP switches it’s important to determine
the nominal audio level of the equipment
connected to the Model 47A’s 4-wire input
and outputs. This may take a little inves-
tigation but is important for obtaining the
best possible Model 47A performance.
The 0 dBu setting is provided specifically
for use when a Model 47A is intercon-
nected with a Clear-Com matrix intercom
system. The +4 dBu setting is appropriate
when standard audio lines with “+4” nom-
inal levels are interconnected. The +6 dBu
setting can be appropriate when intercon-
necting with equipment manufactured in
Europe, such as the digital matrix intercom
systems from Riedel. The +8 dBu setting is
provided specifically when interconnecting
the Model 47A with audio signals associ-
ated with an RTS ADAM-Series of matrix
intercom system. This includes the related
RVON-I/O unit.
When DIP switches 3 and 4 are in their off
(down) position the nominal level is set for
0 dBu. When DIP switch 3 is on (up) and
DIP switch 4 is off (down) the nominal level
is +4 dBu. When DIP switch 3 is off (down)
and DIP switch 4 is on (up) the nominal
level is +6 dBu. When both DIP switches 3
and 4 are in their on (up) position the nomi-
nal level is configured for +8 dBu.
Advanced
Configuration
Four DIP switches are provided on the
Model 47A’s back panel. They allow the
two interfaces to be configured for several
advanced operating modes. Refer to
Figure 6 for a detailed view of these DIP
switches. The available configurations
include auto terminate, auto null button,
and factory test.
Auto Terminate
The auto terminate function is designed to
ensure that each 2-wire-to-4-wire interface
circuit remains stable under most operating
conditions. Specifically, 200 ohm imped-
ances are automatically applied to both
pins 2 and 3 of a Model 47A 2-wire party-
line interface when that interface is con-
figured for external power and no external
source of intercom power is detected on