This Counter64, in bytes, reports the number of bytes the CDMA modem has received specifically during the current, still-active connection. An admin monitors this alongside the current-transmitted counter to see real-time inbound data volume for the active session, useful for identifying an unexpectedly large download consuming a metered cellular link. For example, a spike in this counter during off-hours could indicate an unattended firmware update or backup job is consuming cellular bandwidth unexpectedly.