FYI -  4 seconds = 1 ring in the USA.  so a setting of "16" is 4 rings then forward.

Cisco CallManager 4.2(3) allows you to set this parameter on a per line basis. The field name isNo Answer Ring Duration.

If you are using a .tar file, you need to use the archive command.for your file above, it would be:archive download-sw /overwrite tftp://10.200.238.200/me360x-universalk9-tar.152-2.S.tar