Hi
if its just allowing ACS use ssh instead of telnet remove telnet from vty
no transport preferred telnet
no transport input telnet
change to transport input ssh & transport preferred ssh
You will need to have ssh enabled though aswell globally on the switch
ip ssh ver 2
ip domain-name x/x
ip ssh authentication-retries 3
ip ssh timeout 60
and generate your secure keys
crypto key generate rsa ---- use 1024 for ver2
check with show ip ssh