== How it works ==
To send a byte to the printer, you just need first have to ask verify if it's ready, via bit6 of port B of the PPI located at &F500.
When this bit is 0, you can send a byte. When it's 1, the printer is busy (its buffer is full, it's out of paper, it's turned off, not Online, ...). Note that the system can differentiate between a full buffer and another type of error when the control bit stays at state 1 for too long.