Studio Technologies 92 - Manual (Page 20)

Issue 1, December 2006 Model 92 User Guide
Page 20 Studio Technologies, Inc.
Technical Notes
Theory of Operation
At its core the Model 92 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 37
pins of the male FK37 connector 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 microcon-
troller. Again under software control, the DC
level of signals present on the 37 pins of the
female FK37 connector and the three pins of
the female XLR connector can be measured.
An analog-to-digital converter input on the
microcontroller measures the actual voltag-
es. 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 92. This will
prevent most external DC or static-discharge
signals from damaging the Model 92.
The Model 92’s channel and pin test routines
specify which male (output) pin is active and
then scans the female (input) pins, measur-
ing the voltage present on each pin. The
data is analyzed and interpreted so as to
provide meaningful results to the user.
Specifications
Application: electrical testing of broadcast-standard
DT12-type cable assemblies
Connectors:
DT12 Cable Assemblies: one male and one female
37-pin circular FK37-type
Fanout and XLR: one male and one female 3-pin
XLR-type
Data Link: BNC
12 Volt DC Power In: coaxial power jack, 2.1 x 5.5
mm, locking bushing, compatible with Switchcraft
S760K plug
Power Source:
Internal: 12 volt 1.3 amp-hour sealed lead-acid
battery. Operating time 8 hours minimum with fully
charged battery. Recharge time 8 hours maximum.
External: 12 volts DC nominal, acceptable range
10-15 volts DC; 250 mA minimum recommended
for operation and battery charging. Units shipped
to North America and Japan include a 120 V input/
12 Vdc output power supply.
Master/Slave Operation:
Data Link: modified LIN bus, 1200 bit/s
Maximum Distance between Units: tested to 2400
feet using Belden 1694A coaxial cable and 4000 feet
using standard CAT5E UTP
Dimensions:
Height: 5.0 inches (12.7 cm)
Width: 5.0 inches (12.7 cm)
Length: 11.0 inches (27.9 cm)
Overall Length: 12.5 inches (31.8 cm)
Weight: 5.5 pounds (2.5 kg)
Specifications and information contained in this User
Guide subject to change without notice.