function openSchem(addr) {
  var width = 500;
  if(addr == 1 || addr == 3) height = 700;
  if(addr == 2 || addr == 4) height = 610;
  if(self.screen) { 
    var left = Math.round(screen.width/2 - 225);
    if(left<0) left = 0;                      
    var top = Math.round(screen.height/2 - height/2);
  }
  window.open("/print_contacts.htm?addr="+addr, "schem_window", "scrollbars=1,status=1,width=520,height="+height+",top="+top+",left="+left);
  return false;
}