AT&T's website is only available to current customers wanting to manage their account, while Apple's site is fully functional save for the online store.
Apple put up its familiar "We'll be back" sign, that now cycles through a number of different languages, as it braces for the expected horde of people wanting to be the first to pre-order the new iPhone 5. The connected Apple Store iOS app is also displaying the same message.
AT&T's page went down for maintenance a couple hours earlier than the Apple Store, and includes a splashy placeholder with a timer counting down to the "the big event."
Both companies are most likely taking precautions to not repeat the pre-order troubles seen with last year's iPhone 4S. Overwhelming demand for the last-generation handset caused some customers to receive error messages when ordering began shortly after midnight on Oct. 7, 2011, though the system was sorted out a few hours later.
As of this writing, the websites of the two other major U.S. wireless operators that will initiate iPhone 5 pre-orders on Friday, Verizon and Sprint, are fully functional.