CT-1 Clock/Radio module to sit atop the MP-3 TV tuner, and underneath the CTM640/CTM644 monitor.
The device doesn't seem to be interfacing with the computer, ie. the CPC cannot receive or control the clock/radio signals.
Front
Connectors
The thick black wire is 220-240V supply. The white wire is probably antennae. The other two black wires are unknown, maybe external speaker, in case it doesn't have an internal speaker?
Service Manual
- Amstrad CPC464-6128-GT65-CTM644-MP3-CT1 Amendment Service Manual (pdf) (the CT1 parts list, schematic, component map are found on the last some pages)