Austrian Phonogram recording and manufacturing company, established 1970 and operating under this name until 1979. Combining the Polydor, Phonogram and Amadeo istrative and manufacturing activities (the companies remained separate legal entities though), thereby succeeding Polyphon Schallplatten Ges. mbH.
Took over the former Phonodisc GesmbH can be identified by the following runout stamps / etchings:
Made in Austria (stamped): used to indicate Austrian pressings made from lacquers cut abroad (e.g. Sonopress Gütersloh, Phonodisc Hannover or Baarn).
Use credit: Pressed By.
24 (stamped): Used for masters received from abroad. Use credit: Pressed By.
012 (etched): since 1975 - generally used on Austrian pressings of Ariola Eurodisc GmbH releases (only in addition to Sonopress stampers), either on its own or in combination with 'Made in Austria' (between 1975 and 1977). Use credit: Pressed By (and Mastered At: Sonopress).

Mastering/cutting engineers:
Helmut Leistner (LH)
Credit: Lacquer Cut By (when on their own) + ANV AS or LH.
When in combination with "24": also add Lacquer Cut At - Phonodisc GesmbH

TN preceding 24 indicates the brand of lacquer foils and cutting sapphire: 'Transco/Namiki'.

There are other indicators where the meaning is mostly unknown:
Stamped CK, CKD, CG - between 1976 and 1977.
Stamped CM, CM-B, CM-E, or MC-B, MC-E, or CS-E (until 1977): Long, narrow typeset or small typeset (faint, so can also appear as CH).
C always indicates 'Stereo' ('channelled' - does not appear on Mono recordings).

7" pressings show a characteristic immersion around the center hole. The label area of 7"s and 12"s is always slighly elevated.
This particular disc shape occurs from the 1960s until the end of 7" vinyl production, i.e. stayed constantly the same from Viennola BTG.

In 1979 the plant was renamed to PRS Ges.mbh.