This document specifies 1-pair cabling and can be used in conjunction with all the space-specific standards of the EN 50173 series but especially EN 50173-3 and EN 50173-6. NOTE 1-pair cabling for EN 50173-2, EN 50173-4 and EN 50173-5 is for further study. It delivers 1-pair cabling specifications to extend generic cabling systems according to the EN 50173 series. This document specifies the: - structure and minimum configuration for extension of generic cabling by 1-pair cabling; - interfaces at the service outlet (SO/TO); - performance requirements for cabling links and channels; - implementation requirements and options; - performance requirements for cabling components; - conformance requirements and verification procedures. This document takes into account the requirements specified in application standards listed in Annex C.