I'd like to start over with this phone configuration by resetting to its factory default. I've downloaded http://www.grandstream.com/user_manuals/budgetone100.pdf
but the manual says I need to type in the MAC address before powering down on a reset. The phone's keypad allows me to type in numbers, but not letters. How do I type in letters?
I've locked myself out of the web interface so I can't see much of anything there either - if there were a config file I could upload and test I'd do that, but I'm not sure how.