In preparation of our CCNA exam, we want to make sure we cover the various concepts that we could see on our Cisco CCNA exam. So to assist you, below we will discuss Cisco Router Interfaces.

Summary of Router Interfaces
Model Ethernet Token Ring (DB-9) Sync Serial (DB-60) ISDN2 BRI3 (RJ-45) Async/
Sync
Serial
Ports		 NM Slots Available Wan Slots Available
Cisco 2501 1- AUI 10mb 0 2 0 0 0 0
Cisco 2503 1- AUI 10mb 0 2 1 0 0 0
Cisco 2507 16 Port Hub10mb 0 2 0 0 0 0
Cisco 2514 2- AUI 10mb 0 2 0 0 0 0
Cisco 2520 1- AUI 10mb 0 2 1 2 0 0
Cisco 2610 1- RJ-45 10mb 0 0 0 0 1 2
Cisco 2611 2- RJ-45 10mb 0 0 0 0 1 2
Cisco 2612 1- RJ-45 10mb 1 0 0 0 1 2
Cisco 1720 1- RJ-45 100mb 0 0 0 0 1 2
Cisco 2620 1- RJ-45 100mb 0 0 0 0 1 2
Cisco 2621 2- RJ-45 100mb 0 0 0 0 1 2
1 AUI = attachment unit interface.  
2 ISDN = Integrated Services Digital Network.  

I hope you found this article to be of use and it helps you prepare for your Cisco CCNA certification. Achieving your CCNA certification is much more than just memorizing Cisco exam material. It is having the real world knowledge to configure your Cisco equipment and be able to methodically troubleshoot Cisco issues. So I encourage you to continue in your studies for your CCNA exam certification.