The DRO-375 is a lower cost alternative to the DRO-550 for the budget-minded machinist. It is powered by OpenDRO software so it has all of the same software features as the DRO-550. It omits two scale inputs for a total of three, the RS-232 port, the expansion headers, the SD card interface, and the ability to use the LCD-200 secondary display. For everything else, the DRO-375 and DRO-550 are equivalent.
The hardware capabilities of the DRO-375 are:
50MHz 32-bit ARM7 processor that runs the open-source OpenDRO software
Supports up to three Chinese (24 bit, BCD7, BIN6, and 21 bit formats) and quadrature digital scales
Six digit 7-segment LED display with auto-precision
Five mode indicator LEDs
Twenty-three key keypad matrix
USB interface for programming and control
Dual edge finder inputs
Dual tachometer inputs
JTAG debugging interface
Integrated piezo buzzer for near-zero warning and key-chirp
Constant-current LED drivers for lower heat and flicker-free display
The DRO-375 software is completely open and available via the OpenDRO project. This will allow anyone with an interest to contribute features or fixes. Even if you don't feel comfortable contributing, you can look at the software for more insight on how it works. The OpenDRO software is constantly evolving with new features so check the OpenDRO product page for a complete list.