The MPLI is a versatile DMX512 interface. MPLI stands for Multi-Purpose Lighting Interface. It's basically an ATmega164P (or 644P if more program space is needed) with a power supply, all mounted on a PCB. A SN75176 RS-485 driver chip interfaces the ATmega with the DMX differential bus. 24 GPIOs are connected to a prototyping area (similar to a breadboard) with FETs already connected (for driving heavy loads like LEDs or relays directly).
The ATmega has a 20MHz crystal and a ISP port for programming. The power supply only requires an external transformator to bring down the line AC voltage. A rectifier bridge and smoothing capacitors are included. Two LM317 regulators with pass transistors and heatsinks output up to 4A each at 2 indenpendant voltages. You can adjust the output voltage of each regulator simply by changing the feedback resistors : this makes the MPLI really versatile.
3 DB-09 connectors are provided to simplify the connection to the outside world. The 9th pin on the connector is assignable to either GND, +V1 or +V2 (or anything else really) depending on the use.