Fibre optic interconnecting devices and passive components - Connector optical interfaces for enhanced macro bend multimode fibre - Part 3-81: Connector parameters of physically contacting 50 µm core diameter fibres - Non-angled polyphenylene sulphide rectangular ferrules with a single row of 12, 8, 4, or 2 fibres for reference connector applications (IEC 86B/4837/CDV) (english version)