Question: In a 3GPP-compliant network, when utilizing the USIM Application Toolkit (USAT), which of the following statements is accurate regarding the transmission of specific toolkit commands?
Option 1: TERMINAL PROFILE, TERMINAL RESPONSE, ENVELOPE, and FETCH commands are transmitted on a secure channel, logically separated from other traffic.
Option 2: The Relay Node may restrict these toolkit commands to only be used with READ BINARY and UPDATE RECORD APDU commands for efficiency.
Option 3: TERMINAL PROFILE, TERMINAL RESPONSE, ENVELOPE, and FETCH commands are not issued on a secure channel but are sent over logical channel 0 as per USAT specifications.
Option 4: Support for these toolkit commands is optional for the UICC if the Relay Node does not explicitly request their use.
Explanation: This option correctly reflects the requirement from the USIM Application Toolkit (USAT) specifications that certain commands (TERMINAL PROFILE, TERMINAL RESPONSE, ENVELOPE, and FETCH) are sent over logical channel 0 and are not issued on a secure channel. This is crucial for the proper functioning of the toolkit in telecom networks, ensuring that these specific commands are handled appropriately without the overhead of secure channel protocols.