Phone Number Extension 5858
or
Phone Number Shorthand 5858

5858 by itself is ambiguous. ICUC thinks you might have entered an undefined shorthand telephone number abbreviation or a telephone number extension without a preceding telephone number. To make use of telephone number shorthand abbreviations you must first perform a login from this device. After login, here are some valid ways to use four .ac digits:

5858.ac Ex: Access web site of recent telephone number who's last four digits are 5858
or
c.5858.ac Ex: Calendar for last used telephone number ending in four digits 5858
or
e.5858.ac Ex: Email last used telephone number ending in four digits 5858
or
i.5858.ac Ex: Instant Message last used telephone number ending in four digits 5858
or
s.5858.ac Ex: Get status of last used telephone number ending in four digits 5858
or
800.555.1212.5858.ac Ex: Access web site of telephone number 800.555.1212 extension 5858

more information on telephone number shortcuts, extensions and status codes...