function menu_link(num)
{
	switch(num)

	{

	  case 1:window.location="index.htm" ;break;

	  case 2:window.location="installation.htm" ;break;

	  case 3:window.location="carriers.htm" ;break;

	  case 4:window.location="systems.htm" ;break;

	  case 5:window.location="directory_info.htm" ;break;

	  case 6:window.location="newletter.htm" ;break;

	  case 7:window.location="disaster_recovery.htm" ;break;

	}
}