Wiedmann BTX Modul
The device won't fit to the CPC6128 expansion port (which has different pin-outs as than Joyce) (and for the CPC6128, the connector would need to be mounted top-down).
Although case and PCB are marked "BTX", the chipset looks more like that of a RS232 interface, so it's probably only part of a BTX interface, and additionally requires an external BTX modem.
- Type: PC/HC Adapter
- Country: Germany
- Protocol: CEPT
- Year: 6-1989
- ID Number: 20110
- See also - http://btxmuseum.de/Hardware/ (german)