The MS108EUP is a 8 Multi-Gigabit (2.5G) L3 switch with up 4 PoE++ and 4 PoE+ capable ports for up to 230W of power.
Power is supplied via a 54V 4.7A barrel connector.
A Serial header is found at J3. Pins are Vcc(3.3V, Square), TX, RX and GND. Serial connection is via 115200 baud, 8N1.
Ports 1-4 can also provide power according to 802.3.bt (PoE++) controlled by the BCM59121. Ports 5-8 provide power according to 802.3.at (PoE+) controlled by the BCM59011. Management is done by an auxiliary Nuvoton M0516LDN microcontroller. Communication with the Poe-CPU happens via a serial port, connected to the main CPU's UART1. Optocouplers are used to isolate the two circuits from each other and the communication frames can be sniffed from J4 (3.3V, 19200 baud, 8n1).
To indicate the global device status, two LEDs are present on the front panel. One is labelled 'PoE Max', and is likely controlled directly by the PoE MCU. The other is labeled 'Power', and is used to indicate the device status. This LED appears to be an RGB LED, although it is currently unclear how the three colours are controlled. All ports have a two-pin bi-color LED, used to indicate the link status: green for 2.5G, yellow for 1G/100M. PoE status bi-color LEDs are also available, with green used to indicate the remote device is PoE powered, and yellow to signal a PoE fault status.
This connector is in the PoE power domain, which is isolated from the power domain of the SoC. Be careful when connecting to this port and use a digital isolator.
5 different versions of firmware are shown on the NETGEAR Open Source Code for Programmers (GPL) page , but all link to the same download.
The switch ships with a bootloader based on Realtek's SDK for RTL93xx SoCs and Linux based on Realtek's SDK. It has a web interface for basic management, including firmware updates.