MUSCLE (Multi User Server Client Linking Environment) is an N-way messaging server and networking API. It includes client-side networking APIs for various languages, including C, C++, C#, Delphi, Java, and Python. MUSCLE lets programs communicate over a network via streams of serialized Message objects. The included server program ("muscled") lets its clients message each other and store information in its server-side hierarchical database. The database supports flexible queries via hierarchical wildcarding, and "live" updates via a subscription mechanism.
The SIP Switch is a Web application which allows you to use multiple SIP accounts on the same phone. This lets you use the call plans of different VoIP companies (using SIP) with one IP phone device. It does the third party SIP registration so you can receive all your calls on the sipswitch account. On dial out, you can set prefixes to make your outgoing calls with such or such provider.