CoolTerm
CoolTerm is free and is available for Windows, macOS, and Linux.
Setup for Z88 Communication
Click Options on the toolbar. Pick your serial device (it will be a COM port for Windows users). Set baudrate to 38400 and enable CTS Flow Control.
Click Connect in the toolbar. You will now see the serial port pin status updated in real time.
Sending Files to Z88
Receiving Files from Z88
To minimise delays from handshake timeouts, the sending side should always be started before the receiving.