Special Fectures : . Blue LCD digital display with very classical outer shape . . Exact time and date display , easy to check the Arm/ Disarm history record . . This item is a intelligent code sytem , so you can set as many detectors as you want . . It has 13 alarm zones and 6 group telephone numbers can be set . . 10 seconds voice record can be preset . . It has alarm priority function when the phone line is busy . . This item can be used as a single unit ,or can be network with moniter center . . Optional voiced alarm and mute alarm . . It’ll alarm when the line is cut .