Complex sentence: Upon that change, the original distinction between DMS and PMS disappeared along with the suffix designation; although "Isobarik PMS" remained on price lists until the speaker was discontinued in 1992.
Split into simpler sentences: Upon that change, the original distinction between DMS and PMS disappeared along with the suffix designation. The "DMS" was thus discontinued, although "Isobarik PMS" remained on price lists until the speaker was discontinued in 1992.