@Brook Thanks for your rapid response I'm in Iran and own this modem for more than 4 years. I can ping 192.168.1.1 but cannot test using lan. Because I don't have any ethernet cable right now. This...

I'm using TP-Link TD-W8901N at home but the model is not in the form above! The problem is that I cannot ping or access other devices connected to WIFI. There is two Laptops and two Phones. All has...