Amstrad CT-1 Radio/Alarm-Clock
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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.
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?