Studio Technologies IFB Plus 2007 - Manual (Page 16)

Issue 9, January 2006 Model 2 User Guide
Page 16 Studio Technologies, Inc.
capacitor coupled, with an input imped-
ance of 24 k ohms. Balanced or unbalanced
signals can be connected. The input trim
pot allows signals with a nominal level of
–15 to +10 dBu to be correctly interfaced.
When connecting balanced signals the
audio should connect to the + and – termi-
nals. The shield wire can be connected to
the SHLD terminal associated with the mic
input. Unbalanced signals require a bit more
attention for correct operation. The signal
high lead should be connected to the +
terminal. The signal low/shield wire should
connect to both the – terminal and the SHLD
terminal. Failure to make this connection
can result is large amounts of hum being
induced into the interrupt signal.
If you have connected a signal to the line
input terminals, set the trim pot only after
installing the entire IFB system. Refer to the
Technical Notes section of this guide for
details on setting the trim pot.
The Model 22 contains a monitor mute func-
tion, which is intended to prevent acoustical
feedback if the access station is located
close to the monitor loudspeaker associated
with the Model 2 Central Controller. When
the monitor mute switch is set to the ON po-
sition, the monitor output is muted whenever
an interrupt occurs from that access station.
Model 24 Access Stations
Up to four Model 24 Access Stations can
be connected to two Model 2 units. In this
way the Model 24 units can provide remote
access to the four IFB channels associated
with the two Model 2s. One cable, terminat-
ed with a 9-pin D-subminiature connector
on each end, links the Model 24 with the
Model 2 designated to provide IFB channels
1 and 2. A second identical cable links the
Model 24 with the Model 2 designated to
provide IFB channels 3 and 4. Each Model
24 has an unbalanced microphone input,
a balanced line-level input, five lighted
pushbutton switches, and related circuitry
to access the four IFB channels. Power is
provided by the Model 2 units; an external
power source is not required. A 5-position
screw terminal strip allows connection of a
Studio Technologies Model 11A Gooseneck
Microphone or a line-level signal.
The Model 24 can be mounted using ei-
ther the Model 27A 19-Inch Rack Adapter
or a custom panel cutout. The Model 27A
19-Inch Rack Adapter allows convenient
installation of a Model 24 and a Model 11A
Gooseneck Microphone into one space of
a standard rack enclosure. Refer to Figure
6 for details. Plenty of room remains on the
right side of the rack adapter panel, allowing
you to add custom switches, lights, or jacks
as your installation may require.
A custom Model 24 installation is defined as
any installation where you devise the mount-
ing method! Refer to Figure 5 for a mechani-
cal drawing showing the dimensions of the
Model 24. This will assist you in implement-
ing your own mounting method.
The Model 24 contains two 9-pin D-sub-
miniature connectors, one designated to
connect to the Model 2 designated to pro-
vide IFB channels 1 and 2 (Unit #1) and
the other to connect to the Model 2 desig-
nated for IFB channels 3 and 4 (Unit #2).
Contained on the Model 2 is a 9-pin D-type
female connector that is used to connect
to the access stations. A “straight through”
cabling scheme links the Model 24 units to
the Model 2 units, with pin 1 connected to
pin 1, pin 2 to pin 2, etc. Shielded cable is
required as the audio buses linking a Model
24 to the Model 2s are unbalanced. The
shield should be connected to pin 1 on the