On Android devices, the phrase indicates that a message was transmitted using the Short Message Service (SMS) protocol rather than an internet-based messaging service like RCS or a proprietary app’s data network. For example, if a recipient lacks a data connection or is not using the same messaging application, the message will likely be delivered through the SMS system.
This delivery method ensures communication across different devices and platforms, even when data connectivity is limited or unavailable. Historically, SMS has been a ubiquitous fallback, guaranteeing message delivery regardless of the recipient’s internet access or chosen messaging app. While newer technologies offer richer features, SMS remains a reliable method for basic text communication.
