Question: In SMS subaddressing, as per 3GPP specifications, what indicates the termination of the Short Message Service Center (SC) routing address within the TP-DA field?
Option 1: * (Asterisk)
Option 2: # (Number Sign)
Option 3: @ (At Sign)
Option 4: & (Ampersand)
Explanation: According to the subaddressing rules in SMS, the first '#' encountered in the TP-DA field signifies the end of the SC routing address. Any '*' or additional '#' that follows are considered part of the subaddress digits. This mechanism ensures proper routing and delivery of messages with subaddress information to the intended recipient's SME (Short Message Entity).