• The call time on the phone, for example, is 20 seconds, but the data retrieved from the switchboard is 30 seconds, which does not match the call time between the switchboard and the phone. (How to only calculate time when the called person picks up the phone and stop calculating time when the call ends so that the time on the phone and switchboard can match).
• When the called person does not pick up the phone, the waiting time for the called person to pick up the phone until they do not pick up the phone, for example, is 40 seconds. After hanging up, the switchboard data still returns the call time as 40 seconds. (How to not display call time when the called person does not pick up).

Language and device

• Winform, Net Framework 4.7.2
• Panasonic kx-tes824 switchboard

Connect the computer to the switchboard

• COM port (RS232)

Library

• System.IO.Ports;

Thanks

I searched on the website and Youtube but there were no instructions on how to do it.

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