using usart to communicate with a cop8788

Hi.

I'm new to programming and i have a need to work out usart.

Im looking to build a new alarm siren for my car which now has fishes swimming in it. New ones are no longer available and second hand ones are very rare so i thought i would build one.

Ive traced the circuit in the alarm to the main cpu which is a cop8788 and worked out by hours of probing that the signal is usart with a 1.2k baud rate.

There are 6 different signals transmitted to the siren.

Unarmed
armed
triggered
lock
unlock
unlock driver door only

Each of these inputs gives off a different frequency to give different chirps.

Is all possible with a arduino.