A system designer plays an active role in consulting and design services related to telecommunications and information technologies. This professional will work with system elements such as system architecture, modules, and components

They also work on a large number of complex systems in a distributed system for the development and integration of computer systems in a detailed design document for the development and integration of computer systems.

 Source:  https://www.fieldengineer.com/skills/senior-system-designer They design and configure reusable application systems that must be independent of network applications.