The GC-HDPI-USB includes an HDMI pass-thru adapter that can be used at either end of the HDMI cable. The low profile adapter plugs into any HDMI source and routes 5v to the HDMI +5v line (pin 19) from the external 5v supply.
Typically according to the HDMI specifications the 5V output on the HDMI connector should provide at least 50ma of current to the connected device (sink). However some sources do not provide enough current (or the 5v output may droop as the sink draws power from it). Port powered devices such as some HDMI video switches, splitters, or cable boosters/equalizers rely on the 5v from the source to provide enough current. If you have a source that does not provide enough power on its HDMI output for these types of devices, this inserter can substitute 5v from the external power supply to the downstream device.
The adapter does not provide any current limiting of its own, so the amount of current available is only limited by the external power supply.
It is recommended to plug in the adapter and cable prior to attaching or turning on the power supply. Only use with 5v regulated power supplies. Any damage to the downstream device due to using wrong voltage or excessive power, is the user's responsibility. The 5v output is active when the power supply is plugged in.