Manuals and User Guides for 3Com 3CR17561-91-US - Switch 4500 26PORT Managed 24 10/100 2 Gbe Stackable RJ45. We have 1 3Com 3CR17561-91-US - Switch 4500 26PORT Managed 24 10/100 2 Gbe Stackable RJ45 manual available for free PDF download: Getting Started Manual