AR300M router with iPhone connected to it via WiFi. I have successfully connected a USB drive to the router.
How do I get access to those files from an iPhone or other iOS device?
Do I need to use a certain app?
Can I write files to the USB drive?
The USB files will be shared automatically using samba (windows share).
Some of the andriod phones has samba browser builtin so that you can read/write to the USB. If there is no samba browser you can also install app.
For iphone, there is also app, e.g. file explorer which support samba.
You can also use browser and access the admin UI of the router in your phone. Then you can browser the content of the USB from the UI and download files. You cannot upload using this method.
You do not say what kind of files you want, but if they are media files I suggest trying VLC media player. This, like many others, are clumsy to navigate, but I find I can find and play media files direct from the sd card on my MIFI with no issue.
There is no way to move files to the iPhone with this program that I know of. I either connect my PC to the router or move the card to the PC to transfer files to the media. My phone is generally stuffed with music, so I do not move files directly to it.