A system, method, and computer readable medium for processing short message service terminations in a communication system featuring an IP-based femtocell system are provided. The femtocell system includes a base transceiver station and a Session Initiation Protocol to Internet Operating System adapter. The femtocell system receives message content from a core network over a packet interface that is to be delivered to a user equipment serviced by the femtocell system and depacketizes the message content. The Session Initiation Protocol to Internet Operating System adapter conveys the depacketized message content to the base transceiver station which transmits the message content to the user equipment via a data burst.