Studio Technologies IFB Plus 2007 - Manual (Page 15)

Model 2 User Guide Issue 9, January 2006
Studio Technologies, Inc. Page 15
connected to pin 1 on the 9-pin plugs. For
reference, the following chart displays the
signals associated with the access station
connector:
Pin # Function
1 Common/Shield
2 Interrupt Audio, CH1
3 Interrupt Audio, CH2
4 +18 Vdc
5 Interrupt Control, CH1
6 Interrupt Control, CH2
7 Lamp Voltage, CH1
8 Lamp Voltage, CH2
9 Monitor Speaker Mute Control
For ease of installation, each Model 22 con-
tains two 9-pin D-type female connectors
wired in parallel. This allows signals to be
easily “looped through” on their way to the
next Model 22. For short cable runs, stan-
dard 9-pin video monitor extension cables,
commonly used with personal computers,
are an inexpensive and readily available way
to link a Model 2 with a Model 22. Ensure
that any cable assemblies you purchase use
shielded cable, with the shield connected at
pin 1 of both plugs.
For best performance, a maximum total
cable length of 500 feet should be used to
link Model 22s to the Model 2. Minimizing
the cable length reduces the total exposure
the unbalanced audio buses have to noise
pickup, etc. Cable runs longer than 500
feet are possible but should be carefully
checked for correct operation.
The Model 22 Access Station contains
several configuration switches that must be
set. The input select switch allows the unit to
be set for a mic or a line-level input. In most
cases the Model 11A Gooseneck Micro-
phone, available from Studio Technologies,
will be used with a Model 22. Setting the
switch to the mic position activates the mic
input terminals. The mic input is configured
only for use with unbalanced electret-type
microphones. The + terminal on the mic in-
put provides current limited 5 Vdc to power
the electret microphone. Don’t use a dynam-
ic microphone as damage may occur. The
– terminal is connected to the microphone’s
low signal lead. The connection marked
SHLD is intended for the shield wire of the
microphone cable; it doesn’t carry signal.
The Model 11A Gooseneck Microphone is
an unbalanced electret type, requiring an
external source of DC power. The micro-
phone utilizes a ¼-inch 3-conductor plug
for interconnection. The tip lead brings DC
power to the microphone, as well as hav-
ing microphone audio superimposed on it.
The ring lead is microphone common. The
sleeve lead is a shield connection.
Included with the Model 11A is a mounting
hardware kit. Included with the kit is a
¼-inch 3-conductor jack used to mate with
the microphone’s plug. At the factory a
3-conductor wiring harness assembly is
attached to the jack. The wiring harness has
a red-colored wire, a black-colored wire, and
a shield wire. One end of the red wire is at-
tached to the tip connection on the jack.
The other end should be connected to the
+ terminal on the Model 22’s microphone
input. One end of the black-colored wire
is attached to the ring lead of the jack.
The other end should be connected to the
– terminal on the Model 22’s microphone
input. One end of the shield connection is
attached to the sleeve of the jack. The other
end should be connected to the SHLD ter-
minal on the Model 22’s microphone input.
Setting the input select switch to the line
position activates the line input, and the
associated input trim potentiometer. The
line input circuit is electronically balanced,