Handspring Treo 300 - Manual (Page 120)

Section 6
112 Application-Specific Tasks
Phone Info
ᮣ Phone Number: Displays your phone number.
ᮣ ESN: Displays your phone’s Electronic Serial Number
which uniquely identifies your phone to the PCS network.
ᮣ PRL: Displays the version number of the Preferred
Roaming List.
ᮣ Firmware Rev: Displays the version number for the mobile
communication software on your phone.
ᮣ PRI Checksum: Displays information intended for Sprint
support.
About
PhoneBook Shows version information for PhoneBook.