Manual

Model 44D User Guide Issue 3, August 2018
Studio Technologies, Inc. Page 27
Differences Between Original
and Updated Model 44D Units
This user guide is intended primarily to
support Model 44D units with serial num-
bers of M44D-01151 and later. These “up-
dated” units incorporate several changes
made to the “original” Model 44D units
that were first shipped by Studio Technolo-
gies. The original units had serial num-
bers in the range of M44D-00151 through
00250. This appendix will provide details
on the differences between the original
and the updated units, allowing users to
successfully use both. But it’s first impor-
tant to note that the technical performance
of the original and the updated units are
exactly the same. Audio performance is
equally excellent, the feature set is identi-
cal, and the ability to update the unit’s
application firmware remains the same.
On the original Model 44D the GPI,
GPO, and auxiliary DC output functions
are accessible using a 10-pin “header”
connector that is located on the main
printed circuit board assembly. This con-
nector is only accessible by removing
the unit’s cover. Interfacing with these
three functions requires the addition of
a ribbon-cable assembly that links the
10-pin header with devices located out-
side of the Model 44D’s enclosure. While
fabricating such a cable, or obtaining one
from Studio Technologies, is not a difficult
task, it’s far from optimal. The ribbon cable
will have to exit the enclosure between the
top of the back panel and the cover and
then terminates the functions on a con-
nector that hangs loosely onto the end
of the ribbon cable.
To improve access to the GPI, GPO, and
auxiliary DC output functions the updated
Model 44D design (serial number M44D-
01151 and later) adds a 9-pin subminia-
ture female (DE-9F) connector to the back
panel. In this way the three functions are
now directly accessible using a mating
connector that utilizes a standard 9-pin
male D-subminiature (DE-9M) plug. This
is nice change but doesn’t come without a
cost. To allow physical space for the 9-pin
connector on the back panel, the USB in-
terface connector was moved to a location
on the main circuit board. The cover must
be removed to provide access to the USB
interface connector.
Details regarding the differences between
the original and the updated Model 44D
units are provided in the following
paragraphs.
Figure 9. Back view of “original” Model 44D unit with serial numbers 00151-00250 (left) and “updated”
Model 44D unit with serial numbers 01151-later (right)
Appendix A: Original vs Updated Model 44D