After the internal telephone of Song Guang Building was off-hook, the key could not be opened.

1, check the electric locks on the door. Most of them are electric locks, except for problems, which may be poor contact such as broken wires. Check the wiring of the door crane and the electric lock and the separate power cord of the electric lock respectively.

2. Check whether the unlock key on the extension is normal. Then find out which two lines to the weak current well are control communication lines, and check whether it is short circuit or open circuit, and you can find out the problem.

3. There are two possibilities: the unlocking signal module on the circuit board is faulty, the signal line is broken or the contact is poor. Check the short-term warranty of the extension and the floor (floor platform). The reason may be one of these two places. The easiest way is to call the property.