You layout a PCB or breadboard for the Sparkfun flavor (GND, CTS, VCC, TXD, RXD, DTR), but when you begin troubleshooting all you can find is a CH340 board (GND, +5V, TXD, RXD, DTR, +3.3V).

Build a USB 433 MHz transceiver. At the computer end is a CH340 USB-to-serial chip and the familiar ATmega328 making this a compact copy of the Arduino. At the RF end are a pair of modules for ...