After UICC activation (see TS 31.101), the ME selects a USIM application. If no EFDIR file is found or no USIM applications are listed in the EFDIR file, the ME may then try to select the GSM application as specified in TS 51.011. After a successful USIM application selection, the selected USIM (AID) is stored on the UICC. This application is referred to as the last selected USIM application. The last selected USIM application shall be available on the UICC after a deactivation followed by an activation of the UICC. If a USIM application is selected using partial DF name, the partial DF name supplied in the command shall uniquely identify a USIM application. Furthermore if a USIM application is selected using a partial DF name as specified in TS 31.101 indicating in the SELECT command the last occurrence the UICC shall select the USIM application stored as the last USIM application. If, in the SELECT command, the options first, next/previous are indicated, they have no meaning if an application has not been previously selected in the same session and shall return an appropriate error code.

The ME requests the emergency call codes. For service requirements, see TS 22.101. The ME requests the Language Indication. The preferred language selection shall always use the EFLI in preference to the EFPL at the MF unless any of the following conditions applies:

• if the EFLI has the value 'FFFF' in its highest priority position, then the preferred language selection shall be the language preference in the EFPL at the MF level according the procedure defined in TS 31.101;
• if the ME does not support any of the language codes indicated in EFLI, or if EFLI is not present, then the language selection shall be as defined in EFPL at the MF level according the procedure defined in TS 31.101;
• if neither the languages of EFLI nor EFPL are supported by the terminal, then the terminal shall use its own internal default selection.

The ME then runs the user verification procedure. If the procedure is not performed successfully, the USIM initialisation stops. The ME performs the administrative information request. The ME performs the USIM Service Table request. The ME performs the Enabled Services Table Request. In case FDN is enabled, an ME which does not support FDN shall allow emergency calls but shall not allow MO calls and MO-SMS. If BDN is enabled, an ME which does not support Call Control shall allow emergency calls but shall not allow MO calls. If ACL is enabled, an ME which does not support ACL shall not send any APN to the network. If all these procedures have been performed successfully then 3G session shall start. In all other cases 3G session shall not start. Afterwards, the ME runs the following procedures if the ME and the USIM support the related services:

• SUPI_NAI request if service No. 130 is "available";
• Access control information request and/or UAC Access Identities Configuration procedure;
• Higher Priority PLMN search period request;
• EHPLMN request
• HPLMN selector with Access Technology request;
• User controlled PLMN selector with Access Technology request;
• Operator controlled PLMN selector with Access Technology request;
• GSM initialisation requests;
• Location Information request for CS-and/or PS-mode and/or EPS and/or 5GS;
• Cipher key and integrity key request for CS- and/or PS-mode;
• EPS NAS Security Context request for EPS
• 5GS NAS Security Context request for 5GS;;
• Forbidden PLMN request;
• Initialisation value for hyperframe number request;
• Maximum value of START request;
• CBMID request;
• Depending on the further services that are supported by both the ME and the USIM the corresponding EFs have to be read.

After the USIM initialisation has been completed successfully, the ME is ready for a 3G session and shall indicate this to the USIM by sending a particular STATUS command.

If GSM access is enabled the following procedures shall be performed if the applicable service is enabled and if the ME supports the GSM compact access technology.

• Investigation Scan request;
• CPBCCH information request.

The 3G session is terminated by the ME as follows. The ME shall indicate to the USIM by sending a particular STATUS command that the termination procedure is starting. The ME then runs all the procedures which are necessary to transfer the following subscriber related information to the USIM, if the ME and the USIM support the related services:

• Location Information update for CS-and/or PS-domain and/or EPS and/or 5GS.
• Cipher Key and Integrity Key update for CS-and/or PS-domain.
• EPS NAS Security Context update for EPS domain.
• 5GS NAS Security Context update for 5GS domain.
• Advice of Charge increase.
• Forbidden PLMN update.
• GSM Termination procedures.

Finally, the ME deletes all these subscriber related information elements from its memory. To actually terminate the session, the ME shall then use one of the mechanisms described in TS 31.101.

The ME shall follow the 3G session termination procedure defined above except that the ME shall use the Application session reset procedure as described in TS 31.101 instead of one of the mechanisms to terminate the session.