Samsung SGH-E317CSACIN - Manual (Page 214)

Glossary
214
Security code that protects the phone/SIM against unauthorized
use. The PIN is supplied by the service provider with the SIM
card. It may be a four to eight-digit number and can be
changed, as required.
Roaming
Use of your phone when you are outside your home area (when
traveling for example).
SDN (Service Dialing Numbers)
Telephone numbers supplied by your network
provider and giving access to special services, such
as voice mail, directory inquiries, customer support
and emergency services.