Studio Technologies 93 - Manual (Page 19)

Model 93 User Guide Issue 1, January 2008
Studio Technologies, Inc. Page 19
3. Turn off both units.
4. Designate one unit as master and power
up that unit.
5. On the master unit, select the cable
mode as required for the cable under
test.
6. Identify the type (sex) of the connector
to be connected to the master unit.
7. On the master unit, select the system
mode (master-male active or master-
female active) so as to activate the
connector that will mate with the cable
to be tested.
8. Confirm that the slave unit has automati-
cally powered up and its system mode
is set for slave.
9. Connect the ends of the cable to be
tested to both the master and slave
units.
10. Use the buttons on the master Model 93
to perform the desired tests. The dis-
plays on both the master and the slave
units will display the test results.
Technical Notes
Theory of Operation
At its core the Model 93 uses a fairly simple
method to test the signal paths of the con-
nected cables. Under software control a
test signal can be assigned to any one of
the first 36 pins of the male W1 connector,
pins r, m, and k as a group, and the three
pins of the male XLR connector. This test
signal is a DC level of approximately 4 volts
which is created by way of a pulse-width-
modulator output on the microcontroller.
Again under software control, the DC level
of signals present on the first 36 pins of the
female W1 connector, pins r, m, and k as a
group, and the three pins of the female XLR
connector can be measured. An analog-to-
digital converter input on the microcontroller
measures the actual voltages. All signals
are generated and measured in reference
to the power supply, battery, and data link
common connection.
Resistors, in series with each of the male
and female connector pins, along with
other protection circuitry limit the current
that can come into or go out of the Model
93. This will prevent most external DC or
static-discharge signals from damaging
the Model 93.
The Model 93’s channel and pin test rou-
tines specify which male (output) pin is ac-
tive and then scans the female (input) pins,
measuring the voltage present on each pin.
The data is analyzed and interpreted so as
to provide meaningful results to the user.