I have an old Linksys BEFW11S4 that I am using for LAN file transfers when I am on the road and my phone has a 3G connection. It has an option for WEP security, but it defaults to converting a passphrase into a DeFacto hex key. Is there a way to have the router accept just the passphrase instead of a hex key? And I'm using WEP because it does not have options for WPA1/2
According to the manual for your product here: http://downloads.linksys.com/downloads/userguide/BEFW11S4-v4_ug,0.pdf
So apparently passphrase WEP mode is only compatible with Linksys products. The manual also seems to mention WPA security mode though, so I recommend checking if you have the latest firmware on your router.
You can find more information here: http://support.linksys.com/en-us/support/routers/BEFW11S4