Port

Connect your P3 via a serial RS-232 cable (or USB to Serial adapter) to your computer.

Serial Port

Choose the Computer's serial port that is connected to the P3. Click the arrow to open a list of available ports, then select the port you have connected to the P3. See Finding the appropriate serial port for a USB to Serial Adapter if you're using a USB to Serial Adapter and are not sure which port to choose.

Refresh Port List

Click to update the list of available serial ports, which may be helpful if you plug in a USB to Serial Adapter after the program has started.

Test Communications

Reopens the serial port and verifies that the P3 Utility can communicate with the P3.

Null modem cables, and defective serial cables can echo whatever is sent to them. The P3 Utility cannot tell what device is attached without sending a block of firmware. If firmware load fails on the first block (address x800), it is very likely that the communications cable is not correctly attached to the P3, the cable is defective, or the wrong serial port has been chosen.