The postman always rings

A Dutch start-up called Waleli has come up with a ‘GSM doorbell’ that allows users to answer their doorbell, talk to visitors, and even open the door, whether they are at home or not. Pressing the bellpush calls the user via a built-in SIM’ the visitor can talk to the resident via a small intercom panel next to the bell push, and the GSM doorbell can also be linked to an electronic door release using a code sent from the mobile. When the householder is at home, the GSM doorbell can be switched back to normal non-GSM mode with a single keypush.