After receiving an FSK or DTMF call, the mobile phone will automatically detect and display the number of the call and record the call. If it is in FSK system, the call display signal will automatically refresh the setting of month, day and time, while the setting of year remains unchanged. For DTMF system, all settings will not change. Since DTMF signal only contains the incoming number, it does not contain the date and time of the incoming call. Therefore, when the system receives the DTMF call number, it will assign the set date and time to the call number. If it is a new number, a new call sign will appear at the same time. If the number already exists, a duplicate sign will appear. After receiving a new call, the phone will always display the new call number until it is answered or pressed.
Zhongnuo Electronic Industry Co., Ltd. (hereinafter referred to as Zhongnuo) is a high-tech private enterprise based on customer service and devoted to R&D, production and sales. Its predecessor was Shenzhen Zhongnuo Investment Development Co., Ltd., which was established in 1997.