This part of IEC 61754 covers connectors with protective housings. The housing is defined as
variant 4 in IEC 61076-3-106:2006. These connectors use a push-pull coupling mechanism.
To connect the fibres inside the housing the LC interface is used as described in
IEC 61754-20:2002.
The fully assembled variants (connectors) described in this document incorporate fixed and
free connectors.