Hello @COZZI , the USB-connection does not work on the KPN 12 Box, due KPN uses their own firmware and that is not inclusive the USB-connection.

Thanks for the reply, is there any way I can get the original firmware? My old KPN router had a working USB and I use it for filesharing around the home network. Its a great feature and I’m surprised KPN has left this out of the new routers firmware ..grrrr

@COZZI

Support for a USB disk drive has been removed from all recent KPN devices. I don’t expect it to return. Changing to original firmware is not possible.

I should have kept my old KPN router then !!!  What the hell is the point of having a router with all these features if you don't activate them via the firmware - whoever made that decision clearly isn't a techie … he's an idiot.  its  a Sagemcom router so maybe someone out there will have the original firmware for it … if not it goes in the rubbish tip 

Hi @COZZI  You could consider a NAS. This network device gives you more flexability both at home and “login protected” from outside. A solution used by many people nowadays.

the usb ports can be used for a 4g dongle as in this picture

That’s a picture from the Experia Box v10, this is currently unavailable on the KPN Box 12.

Hi @COZZI, welcome! Jan's answer is correct, the USB port is non-functional on the Box 12. There are no plans to change that.

With regards to this:

Please be advised that the Box 12 remains our property. You may use it while you have a contract with us, but it is not yours to dispose. However, you are free to replace it with a modem/router of your own choosing. More info (in Dutch) about that is here. If you choose to replace the Box 12, do keep it at hand. If you have connectivity issues at any point we may require you to reconnect the Box 12 before we can assist.

I am completely surprised. Called KPN and the technical adviser looked it over and advised me to go to a KPN store since they could physically see more. Maybe it’s one of your iPhone settings? Well no! 
I also tried with an android. So up to the store. Nope! These ports are closed on the modem. According to the assistant it was for security, well more in case someone’s network was hacked and would hold KPN responsible. 
So A: the person on the phone could have told me that. 
and B: Why give me a modem with USB ports that don’t work? For design? 
It’s ok, this problem is so costly for me I’ll spare you the details. 
It is very likely that there will be no workaround, not through a router, a AirPort Extreme or any other solution. I was hopeful by choosing KPN and end up feeling like their employers are extremely Apple unfriendly. 
I have only had KPN for lees then 30 days. So what do you think MY solution will be?

The USB-ports on any KPN modem are solely designated for a 4G USB dongle in case the internet drops out. It's used on our business-internet KPN EEN as a standard part of the subscription and it can be used on consumer-subscriptions as well but then it has to be sent via mail. So no, it's not just a design feature. Having a network attached storage like an Airport will work though. I don't believe our equipment is Apple-unfriendly, I don't like their products but that's a personal opinion.

Ah. Well that sounds a lot more logical then some other solutions or advice. In my case the “problem” or tools I have airport still isn’t the best solution since I want to add it, the external drive I want to connect, to my iPad Pro. Not having a computer currently you would think apple would sync in its own production line. 

However……

https://discussions.apple.com/thread/251856178

and the solution in this article points to another application. And after a bit of luck I found it claims to be able to. 

https://www.stratospherix.com/support/getting-started-with-timecapsule.php

However I don’t have an AirPort Extreme or time capsule.

 And purchasing in order to stay in my own Apple eco system as was advised in the KPN store will still set me back €178.00.

 So I think I found the solution the store did not advice (they just didn’t mention it, pointed me to third party random routers) and that’s your own solution to rent or purchase the Fritz!Box. 

https://www.kpn.com/internet/fritzbox.htm

Note you seem knowledgeable?

If I rent the Fritz!Box will the USB ports be open for my purposes?

 And thank you by the way for responding!

And no I don’t like their products either. 
I think the computer is not the end goal but what you can do with it.

I just wish someone would undercut their market and Windows with something better. 

Hoi @Frank Klaver. De FRITZ!Box die wij leveren is een reguliere 7590 (of de 7583 als je pairbonding hebt), zonder aanpassingen van ons uit. Dus alles wat volgens de AVM knowledgebase met een 7590/7583 kan, kan ook met degene die je dan via ons krijgt. Zie, bijvoorbeeld, dit artikel over het aansluiten van een USB opslagmedium op een F!B 7590.

Jammer wel dat de winkel dit niet even benoemd heeft, sorry daarvoor.