... wireless voice door phone for long distance 500m 1V3 1,2.4G ISM Public Frequency Band:2402MHz-2479MHz 2,Transfer rate:250K wireless ... voice door phone for long distance 500m 1V31,2 ... sensitivity: less than -100.Product Name: Wireless Voice/Non-visual Doorbell 1,2.4G ISM ... 15 beeps, re-timed one minute. wireless voice door phone for long distance 500m 1V3