Almost every DIRECTV box has a USB port.
It's not good for much -- you can hook an AM21 antenna module
up through it and not much more -- and honestly it's a little hard to understand why the port is even there. Over the years there have been whispers that it's used for testing purposes and that it can't be removed without going through the FCC approval process. That explanation is as good as any other, I suppose.
Personally, I've used the USB ports on DIRECTV DVRs to charge my phone for a very long time. If I recall, my old SD TiVo DVR had a USB port, and I know for sure that every HD DVR has had one. Plugging the phone doesn't do anything to the DVR that I've been able to see, and it sure doesn't have any effect on the phone.
I can tell you that the port is a regular 1 amp USB port, meaning that it won't charge an iPad or any other device that needs 2.1 amp power, and it won't quick charge a device like an iPhone or Galaxy S6. Still, you can charge pretty much any phone that charges over USB and using the DVR means you can free up an outlet. That's something, right?