The Galaxy Sub-Rack is the foundation for achieving flexibility, high QoS and rack space savings.The Galaxy Sub-Rack Concept is housed in a 3RU unit designed with a common power and communication interface to all inserted Scientific-Atlanta application modules. The big number of different available application modules can be configured to suit all kinds of needs for the operators and broadcaster due to the flexible concept and the ASI interconnections.Application modules for the Galaxy Sub-Rack physically consist of an interfacing rear-card module and the application front-card module. The rear-connector module holds the connectors but otherwise is kept as simple as possible. All the complexity is on the hot swappable front-card module.