IUSB now has a new phone prefix of 520. This replaces the old prefixes of 237 and 239. See Frequently Asked Questions for information on the implications of the new telephone prefix.

Why did IUSB get a new prefix? The main reason is we were running out of phone extensions (see A History of Phone Numbers at IUSB for more details), but also the new prefix simplifies dialing because callers no longer have to differentiate

The following phone number extensions are available under the new 520 prefix:

• 520-4000 thru 520-4999
• 520-5000 thru 520-5999

Callers can start using the new prefix immediately. The 237 and 239 prefixes will continue to work until July 1 st, 2005, with the exception of all 237-65xx numbers (see 6500 Extensions for more information).

Please note that as of July 13 th, all 65xx extension have been changed!