Permute a string using Bit-Reversal

If you don't see your network's SSID in the iPhone's list of Wi-Fi networks, you can always try the Other option in the Wi-Fi settings screen to manually input the SSID and security settings.

If that doesn't work, you'll probably want to turn on SSID broadcast and temporarily disable your MAC filtering to troubleshoot the issue.

This is an answer generated from the comments.

D. Lichtblau:

Introduced in either version 3 or 4, I forget which. Not sure if it has changed since then.

Mr.Wizard:

Since this is a longstanding feature is there a reason it has not been documented?

D. Lichtblau:

It is not really the most carefully designed of features. (Or so claims the developer who put it in 20 or so years ago.)