Tablet USB Accessories:The Tablet Companion is typicaly used when the vehicle owner uses their own Audio equipment such as a Bluetooth Kenwood head unit, or some other audio external processing and still wants to use USB accessories with the tablet such as an Apple Car Play dongle, Climate Control dongle, relays, camera input etc.
Some people will ask, why can't I just use a regular USB hub and a 12v-5v power stepdown to run my accessores? The answer is because tablets work differently as a USB server than a computer does.
USB-C Tablets:For USB-C based tablets, if a standard powered USB hub is plugged into their port, they will receive charge and can use USB accessories. However, when the power source is turned off (aka your vehicle is turned of) the tablet will then try to provide power to the USB hub to keep the accessories powered, thus draining your tablet's battery.
The Tablet Companion solves this issue with special circuitry that tells the tablet not to provide power to the USB accessories if the tablet is not currently receiving a charge. This saves the life of your tablet's battery when the vehicle's ignition is turned off.
Micro-USB Tablets:In the case of Micro-USB there is a special cable and circuitry required to allow for charge and USB accessory at the same time. A Micro-USB OTG (on-the-go) cable just won't cut it. It will allow for USB accessory, but will not charge the tablet at the same time. A regular OTG cable will also try to power the accessories thus draining the battery.
The Tablet Companion solves this issue with special right angle Micro-USB cable and a circuit board to allow for both charge and accessory at the same time and also not allow the USB accessories to draw power when the tablet is not charging.