Sprint Nextel OVATION U720 - Manual (Page 63)

Section 2C: Menu Options 57
The default lock code is the last four digits of your Sprint Mobile
Broadband USB Modem phone number. (See the “Tip” on
page 58.)
To enable the lock feature:
1. Click the Locked/Unlocked Icon located in the Detail Drawer
of the Sprint PCS Connection Manager interface.
2. The Enter User Lock Code window appears.
3. Enter your lock code and click OK.