The switch is a 24 + 4-port Gigabit L2 switch with up to 185 Watts of PoE+ power on the 24 Gigabit ports.
4 Uplink ports are SFP cages which support 1000 Base-X mini GBIC modules shared with 4 RJ-45 ports
Power is supplied via a 100-240V Type C13 connector.
A unpopulated serial header is found at J12. Pins are Vcc(3.3V, Square), TX, RX and GND. Serial connection is via 115200 baud, 8N1.
There appears to be a unpopulated 14-pin JTAG available at J3.
J1 on the POE control board appears to be an SWD header to program the Nuvoton Chip.
The switch ships with a bootloader based on Realtek's SDK for RTL83xx SoCs and Linux 2.6 based on Realtek's SDK. It has a web interface for all management functions. The board identifies as RTL8382M_8218B_INTPHY_8218B_8214FC_DEMO (Port Count: 28) for the Realtek SDK.
Since the hardware appears to be identical to the DGS-1210-28P but with 256MB of RAM instead of 128MB and a different power supply, support with similar features should be a matter of providing a modified DTS file.