A leased line typically terminates using RJ-48C connector & uses 2 pairs of cables:
Cables - 1&2 for Tx Tip & Ring AND 4&5 for Rx Tip & Ring.
Presentation layer is the one that provides translation services in the OSI model. As stated by Dante, it translates data between different text formats, e.g. ASCII to EBCDIC or ANSI or Unicode etc. Remeber, presentation layer is responsible for the "syntax & semantics" of communication, both negotiation & translation.