Getting Started17#Group4: Configure expansion module key.expansion_module.X.key.Y.type =expansion_module.X.key.Y.line =expansion_module.X.key.Y.value =expansion_module.X.key.Y.pickup_value =expansion_module.X.key.Y.label =expansion_module.X.key.Y.xml_phonebook =To protect against unauthorized access and tampering of sensitive information (e.g.,login password, registration information), you can encrypt configuration files usingYealink Configuration Encryption Tool. AES keys must be 16 characters and thesupported characters contain: 0 ~ 9, A ~ Z, a ~ z. For more information on how toencrypt configuration files, refer toYealink Configuration Encryption Tool User Guide.When configuring some particular features, you may need to upload resource files to IPphones, such as personalized ring tone file, language package file and logo file. Yealinksupplies some resource file templates for the particular features. Ask the distributor orYealink FAE for resource file templates. The following provides information on how tocustomize resource files and specify the access URL for the resource files.Yealink IP phones have built-in system ring tones. You can change the ring type, orcustomize a ring tone and upload it to the phone via auto provisioning.The ring tone file must meet the following:Phone Model File Format Single File Size Total Files SizeSIP-T28P/T26P/T22P/T20P .wav <=100KB <=100KBThe ring tone file must be PCMU audio format, mono channel, 8K sample rate and 16 bitresolution.We recommend you do not edit the MAC-local CFG file. If you really want to editMAC-local CFG file, you can export and then edit it. For more information on how toexport this file, refer to Scenario D Import or export the local configuration file onpage 55. For more information on how to edit this file, refer to Editing Common CFGFile on page 5 and Editing MAC-Oriented CFG File on page 7.