For sausage to be at it's best, it should be smoked at a lower temperature than other meats require. Otherwise, the sausage would overheat, melting the fat and causing it to run out, making the sausage dry and tough.
If the smoker can be kept at 170 degrees or so, it will slowly heat the meat to its ideal done temperature. Keep a remote thermometer probe in one of the sausages, and remove them when they reach 155 degrees. At that point, the meat is done, and it will retain most of its juiciness.