Glossary188PIN (Personal Identification Number)Security code that protects the phone againstunauthorised use. The PIN is supplied by theservice provider with the SIM card. It may be a fourto eight-digit number and can be changed, asrequired.Proxy serverA proxy server resides between a Web client, suchas a web browser, and a real Web server and actsas an intermediary between them. When somepeople browse a web site, their browser is notactually connecting to the web server. The requestfrom their browser goes to a proxy server, and theproxy server makes the request to the web server.A proxy server can improve performance for groupsof users because it caches the results of all requestsfor a certain amount of time. If a user requests aweb page that it already loaded for another user, itreloads the page instead of forwarding the requestto the Web server, which can be a time-consumingoperation.PUK (PIN Unblocking Key)Security code used to unlock the phone when anincorrect PIN has been entered three times insuccession. The eight-digit number is supplied bythe service provider with the SIM card.RoamingUse of your phone when you are outside your homearea (when travelling for example).
