to begin i have to press CTRL-Y, i donīt know how sent that

See this Wikipedia page.

sub ctrl {
    return chr( ord( uc(shift) ) - 64 );
}
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This is the .pl that i use, where i put this sub??

use Net::Telnet ();
$t = new Net::Telnet (Timeout => 5,
                      output_log => "c:\DP\Perl\output.log",
                      Host => "172.20.40.1");
#$t->open("172.20.40.1");
#$t->login($username, $passwd);
@v1 = $t->cmd("\cY");
print @v1;
@v2 = $t->cmd("c");
print @v2;
#$t->print("\cY");
#$t->print("c");
@v1 = $t->cmd("sh ip");
print @v1;
@v1 = $t->cmd("exit");
print @v1;
print "l";
$t->close;
exit;
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I donīt understand the reference?? This script will leave unattended, i not sure that "sub ctrl" do that i want, or maybe i donīt give a good explain . I try to create a script in Perl to do a Telnet to Switch, i describe the step: after i type telnet 172.20.40.1, the switch show me a message: "Press Ctrl-Y to begin", after show a menu, donīt ask me for user or password because i disable that. In the menu i have to press "C" to enter "Command Line Mode" and then write all commands to configurate the switch; next i have to type exit and will back to menu, next press "l" to logout of telnet. OK? All this i try to do a script unattended. Itīs possible? Well,i probe the "sub ctrl" but if any other sugestion will welcome, Thanks a lot. (sorry for my english)

The ctrl example sub is equivalent to the \c built-in construct that you are using. I was under the impression that you didn't understand how control characters are generated from their respective symbol.

As for why your script doesn't work please be more specific. What doesn't work? Have you checked return values and error status after each step? Try to read the Net::Telnet documentation from beginning to end. I'm not familiar with the module but after a brief read I can suggest some starting points for investigation.

Quoting from the docs:

• The default Prompt is '/[\$%#>] $/'
• The methods login() and cmd() use the prompt setting in the object to determine when a login or remote command is complete. Those methods will fail with a time-out if you don't set the prompt correctly.
• Use a combination of print() and waitfor() as an alternative to login() or cmd() when they don't do what you want.

The login possibly times out because "Press Ctrl-Y to begin" doesn't match the default prompt. Also the login will probably stall if you disable password authentication on the switch. Use the docs!