Enables access to the EC2 serial console of all instances for your account. By default, access to the EC2 serial console is disabled for your account. For more information, see <a href="https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/configure-access-to-serial-console.html#serial-console-account-access">Manage account access to the EC2 serial console</a> in the <i>Amazon EC2 User Guide</i>.