The HSD-128 is the first two-channel High-Speed Data Satcom system capable of uncompressed 128 Kbps symmetric bandwidth over the Inmarsat Swift64 Service. During the test flight, the HSD-128 used voice and data channels simultaneously, used air-to-ground and ground-to-air voice calls, browsed the Internet in real-time and sent and received E-mail using an onboard laptop computer.