IEC 61076-2-012:2020 specifies circular connectors with an inner push‑pull locking mechanism of a size derived from and thus being compatible with M12 screw‑locking connectors and with mating interfaces according to IEC 61076-2-101, IEC 61076-2-109, IEC 61076-2-111 and IEC 61076-2-113. A female fixed connector with inner push-pull locking according to this document is intermateable with a correspondingly coded male free connector with M12 screw-locking according to IEC 61076-2-101, IEC 61076-2-109, IEC 61076-2-111 or IEC 61076-2-113. This document covers both: a) power connectors with current ratings up to 16 A and voltage ratings up to 630 V, typically used for power supply of electrical equipment used in industrial premises, and b) connectors for data and signal transmission with frequencies up to 500 MHz. These connectors consist of both fixed and free connectors, either rewirable or non‑rewirable, with M12 inner push‑pull locking as explained above. Male connectors have round contacts from Ø0,6 mm up to Ø1,5 mm. This document covers various types of connectors identified by their "codings" with different contact arrangement, not mutually interchangeable. The design of the inner push‑pull mechanism prevents the unintended mating of the male inner push‑pull free connector with the female connector with M12 screw‑locking even for identical coding. Some styles of free connectors with female contacts covered in this document are equipped with both inner and outer push-pull locking for intermateability also with correspondingly coded male fixed or free connectors according to IEC 61076-2-010.