sub telnet_login  # opens a telnet session to "host"
  {
    use Net::Telnet;  # initialize the telnet module
    my ($username, $password, $host, $shell) = @_;
    # takes function arguments and stores them into appropriate variables
    $$shell = new Net::Telnet ('Timeout'=>'7',
                               'Errmode'=> sub { report_error("telnet","Username or Password failed"); },
                               'Prompt'=> '/.*([\$#\%>~]|\@\w~\$|\\\[\\e\[0m\\\] \[0m)\s?/' );
    # initalizes a telnet object sets a prompt to expect sets a timeout sets error-checking

    $$shell->open(Host=>$host);            # opens the object
    $$shell->login($username,$password);  # login to the telnet session
  }