Accu-Keyer

Some stills of an Accu-Keyer from the mid 70's.
The Monolog is in CW. So if you can not decode CW with your ear. Then I suggest downloading some free CW software. FLDIGI is free and has versions for many OSs. Once you have some software you can then continue to monitoring CW from online streams, over the air signals or from SDR\s that can be found on the web. I suggest experimenting with a site that you can find by googling Kiwi SDR maps.