Studio Technologies 240 - Manual (Page 29)

Model 240 User Guide Issue 1, August 2013
Studio Technologies, Inc. Page 29
available worldwide from sources such as
Digi-Key, website www.digikey.com.
To make the process of connecting to
the Model 240’s headers a simple task an
interface cable kit, part number 31087, is
available from Studio Technologies. Each
kit includes five cable assemblies and a
length of heat-shrinkable tubing. Each cable
assembly consists of a mating connec-
tor with three color-coded wires attached.
These wires, approximately 12 inches in
length, allow convenient soldering to a
connector slated to be installed in a spare
location on the Model 240’s back panel.
For reference, the wire color for pin 1 is
gray, pin 2 is yellow, and pin 3 is blue.
The heat-shrinkable tubing is provided so
that the connector solder cups can be in-
sulated from each other. It will also provide
some strain relief to the solder joints. Be
certain to slip the desired length of tubing
over the wire prior to soldering a connec-
tion! (If this writer had a dollar for every time
he forgot to put tubing on a wire (or slip on
a connector shell) before making a solder
connection…)
The 3-position headers on the Model 240’s
main circuit board assembly are located
close to their related input or output
connectors. For details please refer to
Appendix B at the end of this guide.
Remote Switch Input
Connections
Provision has been made on the Model
240’s printed circuit board assembly to
allow external switches or contact closures
to control the talk-to-main output functions.
Two 3-position headers provide access
to the circuitry associated with these func-
tions. Electrically the contact inputs are in
parallel (connected directly together) with
the normally open (not shorted) contacts
on the four front-panel pushbutton switch-
es. Each switch input circuit is “active low,”
with a 10 k ohm resistor connected to +5
volts acting as a pull up. A combination of
resistors and capacitors provide ESD pro-
tection, isolating the contact from the unit’s
microcontroller integrated circuit. Refer
to Appendix B at the end of this guide for
connection details.
Relay Contacts
The Model 240 provides five normally
open (not shorted) relay contacts for use
in specialized applications. A relay contact
is associated with each of the four main
output functions. Whenever a talk function
is active its associated relay contact will
close (short). The fifth relay closes (shorts)
whenever any of the talk-to-main output
functions are active. No matter whether
one, two, or all the talk functions are active
the relay will close (short). This “any talk”
contact can be considered to be respond-
ing to the talk functions as a logical “OR”
function. The five relays operate under
software control and are always active,
whether or not connections are made to
them.
Some “head scratching” or “brainstorm-
ing” should lead to a number of interest-
ing ways to take advantage of the relay
contacts. Applications could include keying
wireless transmitters, activating “on air”
lights, and muting loudspeakers systems.
To utilize any of the relay contacts does
require the talents of a qualified technician.
This is because the Model 240’s enclosure
must be disassembled and the desired
wiring scheme implemented. For detailed
information on interfacing with the relay
contacts refer to Appendix B at the end
of this guide.