Serial Interface (dev. #03)

Device allows ZX Spectrum to communicate with external peripherals and PC through the most popular communication interfaces used in automation: UART (RS-232), SPI, I2C, and USB. Thanks to the interface, you can connect to the computer most of the devices designed for Arduino: temperature/pressure/pollution sensors, displays, relays, LEDs, LCDs motors, servos and many, many more…

Now available on eBay. Follow this link.

One of the attractions of the device is the ability to talk to it from a simple BASIC terminal.
Fragment of the manual.