The USB port on the side of the Simplifi unit is for USB 2.0 and 3.0 compatible devices. While many other use cases can be recommended using the USB port, Simplifi currently supports two use cases noted below;
Device charging and power access via USB Charger. This could be used for charging your phone, computer peripheral or other USB charging applications. Currently Simplifi doesn't accept power via USB and therefore has to be plugged into a wall jack for electrical power.
USB to Ethernet Dongles - This is most commonly used in failover applications using the included USB to RJ45 Ethernet dongle. In simple terms, a mainline ISP (Internet Service Provider) would be connected into the Ethernet port of the Dongle and then connected via USB to the Simplifi. In this use case, Simplifi acts as a Router with your existing ISP provider -or- by adding a SIM Card into Simplifi, if and when the mainline ISP is disconnected, Simplifi will continue to provide seamless Internet