It's a good idea to place variables _transmitPin, _receivePin and _inverse_logic in the public or protected section to make it easier to inherit.

[veryblackcat]

https://github.com/arduino-org/ArduinoCore-primo/blob/9cfaadcb15b0750070162c57107955481ee2f71f/libraries/SoftwareSerial/SoftwareSerial.h#L41