R4-24 [129] If a SONET NE supports STS-1 electrical interfaces, the
following apply:
… •The transmitter shall generate an interface signal that meets the
criteria in Table 4-19 for the entire range of interconnect cable
lengths of 0 to 450 ft between the transmitter and the interface.
… •The receiver shall accept any interface signal that conforms to
the criteria in Table 4-19 (at the interface), and that propagates
through a jumper cable (if used, may be up to 27 ft) and an
additional length of interconnect cable, which can also be up to
450 ft.