IEC 61076-2-109:2014 describes circular connectors with IP 65/IP 67 degree of protection and suitable for data transmission with frequencies up to 500 MHz. Applications include, but are not limited to, vision systems and data acquisition. These connectors consist of fixed and free connectors, either rewireable or non-rewireable, with M 12 x 1 screw-locking. Male connectors have round contacts ∅ 0,6 mm. This standard covers two different types of connectors, denominated X and H, with different contact arrangement, not mutually interchangeable, but with common ratings and purposes.Keywords: Connectors, Circular Connectors, Data transmission