CMR cable stands for "Communications Multipurpose Cable, Riser". It is a cable jacket fire resistance rating defined in Article 800 of the NEC. CMR cable is also referred to as "riser-rated cable" and designed to prevent fires from spreading between floors through risers or vertical shafts. While LSZH is the short form of Low Smoke Zero Halogen.These cables are constructed with jacket material free from halogenic materials such as chlorine and fluorine as these chemical have toxic nature when they are burned. LSZH cables are used mainly in Europe.For the details clarification, please check the link: https://community.fs.com/blog/ethernet-cable-jacket-ratings-cm-vs-cmr-vs-cmp.html by R***r on 01/09/2021