This is horribly weak.
First off, the open source linux telephony engine is called "Asterisk", not "Asterix".
Secondly, the statement "...by diverting data to an Asterix (Linux-based software PBX), where crypto isn't supported so that conversations default to plain text, cryptographic researchers discovered." is no "discovery" by any means. Not being able to defeat DECT head on, but running it though MOST PBX engines based on the SIP protocol, which is used by an incredibly large number of PBX systems, is as worthless an observation as stating "clipping a telephone test set in line with the DECT device also allowed bypassing DECT".
Sniffing a SIP/RTP based call has nothing to do with DECT, is not specific to Asterisk, is not a "discovery", and seems only to serve here as some attempt at validating research that yielded no real discoveries about cracking DECT.