Swan EMS Home Swan EMS, Cable Assemblies, PCB assemblies, Panel Assemblies, Box Build Assemblies Swan EMS are a dedicated electronics subcontractor specialising in cable assemblies, custom harness cables, Box & panel build and PCB assemblies, integrating these into a complete systems. Swan EMS was founded in 1999. We work with customers at the earliest opportunity and offering design consultancy services to support the standard build to print service.