DCF600USB: DCF77 Radio Clock for the Universal Serial Bus (USB) – Welcome to Al Mamaas Trading
DCF77 is a German time signal that can be decoded using an arduino
File:Module DCF77.jpg - Wikimedia Commons
DCF77 Receiver Modules | Blinkenlight
Homebrew DCF-77 Transmitter
0107 | GUDE Expert mouseCLOCK USB II DCF77 USB | Distrelec Export Shop
DCF77 emulator with ESP8266 | Elektor Magazine
DCF77 Optical Antenna Link - DOAL
USB Supported DCF77 Receiver Known as FunkUSB - EEWeb
Circuit board for DCF77-Receiver with Signal level meter - Share - PCBWay
DCF77 USB Interfacen
DCF600USB: DCF77 USB Radio Clock
How to build a DCF77 HID USB real-time clock (dcf77-hid-usb-rtc) for usage with Linux systems « Adafruit Industries – Makers, hackers, artists, designers and engineers!