Developer Erik Salaj over at WINSOFT has a whole suite of Com Port components for Firemonkey in Delphi and C++Builder. The various Com Port components give you access to the Com Port on Android, OSX, and Windows. It does not appear that there is any support for IOS though. You can communication with all kinds of different devices using the Com Port like printers, sensors, joysticks, and all kinds of Internet of Things devices. There are a number of different components for Com Port access on Android which include connecting via Serial, support for FTDI FT311D and FT312D devices, support for Prolific devices, USB connected devices including FT232R, CDC/ACM (Arduino Uno), CP2102 and CH34x chips, and even more USB Serial devices including CP210x, CP2130, CDC, FTDI, PL2303 and CH34x devices. The Windows and Mac OSX Com Port components are also available for standard serial port communication. I believe there is a Windows version for VCL and one for FMX. On the Windows side there is even support for Protocols 3964 and 3964R. WINSOFT is a third party library integration powerhouse with over 50 different third party libraries wrapped in easy to use Delphi and C++Builder components. The components are commercial but there are free trials available and come with full source code after purchase. Additionally, you can buy ALL of the components together at a very steep discount. The bottom line is if you need to connect to any type of serial device from Android, OSX, or Windows using Delphi or C++Builder you should check these components out because they can save you a lot of time. Accessing the Com Port becomes as easy as "ComPort.ReadAnsiString;" and "ComPort.WriteAnsiChar(AnsiChar(Key));".
Check out ComPort for VCL in Delphi 10 Berlin.
Check out ComPort for Android with Firemonkey in Delphi 10 Berlin.
Check out ComPort for Android FTDI FT31xD with Firemonkey in Delphi 10 Berlin.
Check Out ComPort for Android Prolific with Firemonkey in Delphi 10 Berlin.
Check Out ComPort for Android USB with Firemonkey in Delphi 10 Berlin.
Check out ComPort for Android USB Serial with Firemonkey in Delphi 10 Berlin.
Check out ComPort for FireMonkey on Windows in Delphi 10 Berlin.
Check out ComPort for OS X in Firemonkey for Delphi 10 Berlin.