Manual
Issue 3, August 2019 Model 374A User Guide
Page 20 Studio Technologies, Inc.
MODEL 374A
INTERCOM BELTPACK
flash memory by way of a USB interface.
The Model 374A implements a USB host
function that directly supports connection
of a USB flash drive. The Model 374A’s
MCU updates its application firmware
using a file named M374A.bin.
The update process begins by preparing
a USB flash drive. The flash drive doesn’t
have to be empty (blank) but must be in
the personal-computer-standard FAT32
format. Save the new application firmware
file in the root directory with a name of
M374A.bin. Studio Technologies will sup-
ply the application firmware file inside
a .zip archive file. While the application
firmware file inside of the zip file will ad-
here to the naming convention required
by the Model 374A, the name of the
zip file itself will include the file’s ver-
sion number. For example, a file named
M374Av1r2MCU.zip would indicate that
version 1.2 of the application firmware
(M374A.bin) is contained within this zip
file.
Once the USB flash drive is inserted into
the USB interface, located on the main cir-
cuit board under the cover, the unit must
be powered off and again powered on.
At this point the file will automatically load
into the processor’s flash memory. The
precise steps required will be highlighted
in the next paragraphs of this guide.
To install the application firmware file
follow these steps:
1. Disconnect power from the Model
374A. This will entail removing the
Ethernet connection that is providing
PoE power.
2. Remove the cover from the Model
374A. Begin by removing the four Phil-
lips-head machine screws (#1 screw
driver tip), two per side. Be certain to
save the screws so that re-assembly
will be fast and painless. Then carefully
slide the cover forward to separate it
from the level controls and buttons and
then lift it off.
3. Locate the USB connector on the main
circuit board. It’s near the channel 1
button. Insert the prepared USB flash
drive into it.
4. Apply power to the Model 374A by
connecting to a Power-over-Ethernet
(PoE) Ethernet source.
5. After a few seconds the Model 374A
will run a “boot loader” program
that will automatically load and save
the new application firmware file
(M374A.bin). This will take only a few
seconds. During this time period the
channel 4 button LED will flash slowly
in alternating colors. Once the entire
process is over, taking approximately
10 seconds, the Model 374A will re-
start using the newly saved application
firmware.
6. At this time the Model 374A is operat-
ing under the newly saved application
firmware and the USB flash drive can
be removed. But to be conservative,
remove PoE power first and then re-
move the USB flash drive.
7. Confirm that the desired application
firmware version has been correctly
saved. This can be done by pressing
and holding the channel 4 button, ap-
plying PoE power to the Model 374A,
and then “reading” the application firm-
ware version number by first observing