MC-Squared: Designed real-time Digital Access Cross-Connect switch control software in C on Sun SPARCstations for COMSAT Mobile Communications' High-data-rate Gateway Switch (HGS) to interconnect terrestrial ISDN networks with INMARSAT Std A and Std B Land Earth Stations (LES) and provide global 56/64Kbps high-speed data services (A-HSD and B-HSD) to mobile users across the globe.  Developed hardware-independent Cross-Connect Manager process and low-level hardware-dependent command compiler and switch communications processes.  The HGS software also compensates for incompatibilities between D-channel signaling to the terrestrial network and to the Access and Control Equipment (ACE) and INMARSAT-B terminals.