Hi!
Edit the file /etc/inetd.conf
There is a line:
#telnet stream tcp nowait root /usr/sbin/tcpd in.telnetd
Remove the comment from that line and save.
Then send a HUP to inetd to make it re-read the config file.
~> ps -aux | grep inetd
~> kill -HUP <whatever PID it has>
Enjoy.
Regards
Martin