Can I use Cisco 2821 DRAM memory on Cisco 2811?

How do I prevent that when I type my username and password the echo back ?User Access VerificationUsername: 177484i4177484i4Password: 95959595 

Hi there,I have 3620 router which can handle 1024 vc's ( ATM OC3) I want to replace it with cisco 7206VXR ( ATM WAN OC3+) which can cater for 8191 vc's. The problem is that the the vc's comes up on the new router ( 7206) but IP connectivity through a...