Foca Max is a USB to TTL serial converter board. With a 8-26V DC external power input, Foca Max brings a stable power source and convenience of USB to TTL communication for all series and sizes of Nextion HMI display.
Foca Max can be power supplied by USB only or USB together with external DC 8-26V. For Nextion HMI display size less than 4.3'', you can only use the USB for power supply. For a size large than 4.3'', an external DC 8-26V for power supply is recommended.
More information is available on the website of Itead.