The Short Message Service Centre (SMSC) is a vital component within a GSM network, tasked with the responsibility of handling the transmission of short messages (SMS). All messages are routed through the SMSC, which functions by storing the messages, identifying their intended recipients, and making attempts to deliver them. In cases where immediate delivery is not possible, the SMSC follows a predefined retry schedule. Additionally, when a mobile phone is powered on or enters the network’s coverage area, the SMSC will also make further delivery attempts. Upon successful delivery to a mobile phone, an acknowledgment is typically sent back. Generally, if a message cannot be delivered to its destination within two days, it is removed from the system.

To enable this functionality, users must program the SMSC’s number into their mobile phones.