Samsung SGH-E105CSATMB - Manual (Page 109)

Network Services
106
Caller ID
You can prevent your phone number from being displayed
on the phone of the person being called.
Note: Some networks do not allow the user to change this setting.
The following options are available.
Default: the default setting provided by the network is
used.
Hide Number: your number is not displayed on the other
person’s phone.
Send Number: your number is sent each time you make a
call.