This read-only counter tracks the number of SMS messages successfully received and stored on the router, noting these are mirror copies of SMS also stored on the modem or SIM. An admin uses this to confirm inbound SMS messaging, such as carrier notifications or remote command messages, is actually reaching and being recorded by the router. For example, if a remote-management workflow relies on incoming SMS commands and this counter isn't increasing, the admin knows messages aren't being received or stored, pointing to a possible SIM or carrier-side issue.