This standard specifies the characteristics of receptacle connectors with two hole fixing in the family of circular single channel fibre optic connectors incorporating ferrules for aerospace series single core optical cable in accordance with EN 4532. Connector interface dimensions, table of tests and qualification approval requirements, are contained in the Technical specification EN 3733-001. EN 3733-002, List of product standards, includes the listings of product types, codification and applicable combinations of product types.