Question: In a GSM/UMTS system, what is the primary difference between Short Message Terminated (SM MT) and Short Message Originated (SM MO) basic services?
Option 1: SM MT supports up to 160 characters, while SM MO supports up to 140 octets.
Option 2: SM MT involves transferring a short message from the Short Message Service Center (SC) to a Mobile Station (MS), whereas SM MO involves transferring a short message from an MS to a Short Message Entity (SME) via an SC.
Option 3: SM MT requires an active speech or data call for message delivery, while SM MO does not have this requirement.
Option 4: SM MT generates a delivery report only upon successful delivery, while SM MO generates reports for both successful and failed deliveries.
Explanation: The correct answer highlights the fundamental distinction between SM MT and SM MO services. SM MT is centered around delivering short messages from the SC to an MS, providing feedback on delivery status. In contrast, SM MO focuses on forwarding short messages submitted by an MS to an SME via the SC, also with delivery status reports. This difference underscores the direction of message flow and the roles of network entities involved in each service.