Equipment (1) for services interconnection of a tractor-trailer combination has an arm (2) mounted for sliding lengthwise transversely of the trailer-front on bearings (3) of a horizontal guide (4), with its leading end carrying connectors for services connections from the tractor. The arm (2) is restrained against damaging lateral forces in each of its extended and unextended conditions by projection-within-socket engagement between pins (10) and pin-receiving holes (11) or slots. In an adaptation of the equipment (40), the leading end of an extending arm (45) has a connector plate (46) that carries services-connectors (47-48) outwardly and downwardly beyond the side of the trailer for access from ground-level. The trailing end of the arm (45) is pivoted (50) to a slider (51) that slides along an upwardly-inclined guide (52) with an intermediate location of the arm (45) constrained to slide along a fixed horizontal rail (54) so as to establish a downward inclination of the arm (45).