* It might also be a Serial and Parallel interface being made years later in 1992 (according to http://www.retroisle.com/amstrad/cpc/Articles/hwlist.php).
The above descriptions do more or less conflic conflict with each other, the danish article from 1985 sounds a bit more trustworthy, but maybe both descriptions are correct (and the whole package consisted of both a modem, bundled with serial/parallel interface).