... the alarming lamp would light to prompt. How does the wireless emergency call system work?When the old, the disabled, patient ... .5MHZ can be customizedWorking voltage: AC100-240V,DC 12VApplications:MMcall wireless emergency call system can be used in home, villa, senior ... .MMcall Customerized products, no stock, if needed, please contact us. Wireless emergency call system with door LED alarm lamp