I used to use 7911 ipphones and there wrere a good feature which i mention it dial auto complete , which when i press any no in key pad like 5 , screen showed me all dialed No that start with 5 . Unfortunatelly this feature has been removed in 7821 . Is there any way to enable it ?
This feature is not available on 78XX IP phones. You may check with TAC for any enhancement defects open for the same, else you can engage your Cisco acct team for a feature enhancement request.
Just to add a note to the great info from my friend Manish (+5), it looks like there is a Bug/Enhancement request open for this issue that you can follow to see when it's fixed;