Right, I forgot about the pull-up resistor. It will take care of pulling the line back HIGH when the pin changes to input, even better, one less step.

Revised:

- all PICs define BUSY LINE pin as INPUT.

- pull-up resistor on BUSY LINE.

- to transmit, a PIC checks if BUSY LINE is HIGH (available), BUSY LINE pin set LOW (busy). Pin is automatically set as OUTPUT by PBP LOW command.

- once finished transmitting, BUSY LINE pin is set as INPUT.

- pull-up resistor pulls BUSY LINE back to HIGH (available).

Thanks Ron!

Robert