From SpinetiX Support Wiki
The type and number of USB ports varies depending on the player model:
- HMP400, HMP400W
- HMP350, HMP300
- 2 x USB 2.0 ("Hi-speed")
- The USB ports can be used only to update the firmware.
- HMP200, HMP130, HMP100
- 1 x USB 2.0 ("Hi-speed")
- The USB port can be used to update the firmware, to connect USB / serial / USB cellular modem devices, to extend the player storage, and to play content directly from the USB flash drive. It is limited to three endpoints (a USB device might have a varying number of endpoints), nevertheless, the HMP can support a greater number of USB devices through software emulation - this is controlled by the "Support large number of USB devices" option from HMP Control Center > I/O Automation page > USB Settings tab; when mixing full or low-speed devices with high-speed hubs this option should be disabled for compatibility.
- Video input via the USB port is only supported on HMP400/W (DSOS WIDGETS or higher)- for the other models, check out the video streaming via Ethernet feature.
- Multiple USB devices can be connected through USB hubs to the HMP at the same time, but only one USB storage device can be used as external storage.
- The USB ports on the player cannot be disabled, however, unless the HMP is set to look to the USB storage for content, a malicious user could not interfere with the displayed content. For fail-safe security protection of the USB port, consider using a physical lock (like these USB port blockers from Lindy).
Power over USB
In line with the USB power standards, the HMP400 and HMP400W players supply up to 900mA of current at 5V ⇒ 4.5 W, while the other players supply up to 500mA of current at 5V ⇒ 2.5 W. If a device draws more than the allowed amount, the port will be shut down to protect the player.