"why tablo has 2 USB inputs"

I just bought Tablo 2 tunners. What is the second USB input slot for?

Nothing at the moment.

@joeb1

I use the 2nd USB Port to power the Laptop Cooling Fans my Tablos are sitting on.

Chas

So the second port can then also be used to power the amp for an antenna such as the Mohu + Jolt (amp).

I think this use was not recommended if I remember correctly.