It's called the International Softswitch Consortium. First glance implies that it has to do with software. If memory serves, there was even once a software product so named that converted word processing documents composed with one word processing package to another package's format. Today it's done within each word processing package - e.g. the conversion between Microsoft Word and Corel WordPerfect. Both require hardware, wires and software.
Circuit switching has the long ago image of a switchboard operator making physical connections.
Although, because the PSTN world has become almost fully digital, the PSTN may have as much software as does the IP world. Each is a veritable universe of microprocessors floating in a sea of microprocessor software. The consortium does not set standards. Three that it is currently promoting are the ITU's H.323 standard and two IETF protocols. The RTP governs the flow of real-time content across an IP network once a session has been initiated by SIP between the content sender and receiver.