Nitsuko DS01 Key Service Unit (Refurbished)The ONYX VS and ULTRACOM DCS are the smallest members of the ONYX and ULTRACOh1 family of digital telephone systems. Modular design allows these systems to respond immediately to a business' changing requirements and growth. They are expandable from 12 extensions and four lines to 48 extensions and 16 lines. Like the rest of the ONYX and ULTRACOM family, the VS and DCS are unique in their adaptability, cost effectiveness and ease of use. With ONYX VS