● Closed user group — You can specify a group of people to whom you can calland who can call you (network service).● Confirm SIM services — You can set the device to display confirmationmessages when you are using a SIM card service (network service).In the offline or flight profiles, you may need to unlock the device and change tothe calling profile before making a call.When calls are limited to closed user groups, calls may be possible to the officialemergency number programmed into your device.Certificate managementSelect Menu > Settings and Phone > Phone mgmt. > Security > Certificatemanagement.Digital certificates should be used if you want to connect to an online bank oranother site or remote server for actions that involve transferring confidentialinformation. They should also be used if you want to reduce the risk of viruses orother malicious software and be sure of the authenticity of software whendownloading and installing software.Select from the following:● Authority certificates — View and edit authority certificates.● Trusted site certificates — View and edit trusted site certificates.● Personal certificates — View and edit personal certificates.● Phone certificates — View and edit device certificates.Digital certificates do not guarantee safety; they are used to verify the origin ofsoftware.Important: Even if the use of certificates makes the risks involved in remoteconnections and software installation considerably smaller, they must be usedcorrectly in order to benefit from increased security. The existence of a certificatedoes not offer any protection by itself; the certificate manager must contain correct,authentic, or trusted certificates for increased security to be available. Certificateshave a restricted lifetime. If "Expired certificate" or "Certificate not valid yet" is© 2008 Nokia. All rights reserved. 137
