CISCO2503-RF - Cisco 2503 Router 2 x Serial, 1 x ISDN BRI Router Chassis
Cisco Systems 2500 Series Model 2503 Rack Mountable Dual Serial Network Router | eBay
Routers & Cisco IOS. - ppt download
Replacing the Boot ROMs in the Cisco 2500 Series and AccessPro PC Card Routers
My grandfather gave me a Cisco 2500 series router and it looks like it predates Ethernet. How can I get this working? What are all these ports, what signals do they use,