Is there a way to publish keyboard events (using key_teleop for example) to a serial port?

Hi, I've been looking at ways to publish keyboard commands to a UART serial port and the top result keeps pointing me to rosserial, but I'm not entirely sure this exactly fits my needs. Ideally, I want to be able to send keyboard events to my flight controller through PPM signals because I already have the hardware that would send signals from a serial port to my flight controller. This is how I envision it would go from all the materials I have: KEYPRESS (Twist message) ==> UART SERIAL PORT (probably ttyS1) ==> PPM ENCODER (not an Arduino) ==> FLIGHT CONTROLLER I found that I can publish Twist messages using either the key_teleop module or teleop_twist_keyboard, but I'm stuck as to how to send this to a serial port (i.e. ttyS1). Would I simply need to write my own ROS node and use pyserial (since I would be writing in python) to open the port and pass the message in? Or can I use rosserial somehow to pass in Twist messages? Thank you in advance and please excuse me for asking a noob question. Trixie