procedure WriteChar(aCh : AnsiChar);
Writes a single character to the terminal.
The character written to the terminal will go through the same steps that a character that had arrived from the serial device would go through. In other words, the character is first passed to the emulator, which decides what to do with it. If the emulator decides that the character is part of a terminal control sequence, it would appear as if the character had not been accepted (it would not appear on the display) when in reality it had.
The terminal will accept a character written with WriteChar at any time, even when it is actively receiving data from the serial device. Be aware that under these circumstances, the character written with WriteChar will intermingle with data from the serial device and may cause some bizarre behavior and displays.
Note also that the lazy write mode still applies to text written to the terminal with WriteChar. If UseLazyDisplay is True, the text will appear at the appropriate time. The new data can be forced to be displayed in this case by calling the Update method.