NOS Cisco Systems 2500 Series Model 2503 Rack Mount Dual Serial Network Router | eBay
Cisco 2503 Router | eBay
Cisco 2500 Series Model 2503 Dual Serial Router
Cisco 2500 series - Wikipedia
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,
Cisco2503 - Knowledge Computers
NOS Cisco Systems 2500 Series Model 2503 Rack Mount Dual Serial Network Router | eBay
Cisco Systems Cisco 2503 ISDN 2x Port | Router | Netzwerk | Netzwerk & Server | Delwi IT-Remarketing GmbH