A telecommunications system (950; 830), comprising: at least two trunk cables (920, 920'; 820, 820') comprising at least four optical fibers and terminals (922, 922', 924, 924'; 822, 822', 824, 824') at opposite ends of the fibers, the terminals (922, 922', 924, 924'; 822, 822', 824, 824') including a plurality of ports, each of the optical fibers being associated with a respective one of the trunk terminal ports; and two substantially identical transition devices (900, 900'; 800, 800'), each of the transition devices (900, 900'; 800, 800') comprising: a first set of at least four optical fibers, each of the optical fibers having a trunk end and a transceiver end; a single transceiver end terminal (904, 904'; 802, 802') having a plurality of transceiver ports, each port connected with a respective one of the set of optical fibers at its transceiver end, wherein a first axis of symmetry divides the ports; a plurality of trunk end terminals (902, 902', 903, 903'; 804, 804', 806, 806'), each of the trunk end terminals (902, 902', 903, 903'; 804, 804', 806, 806') having a plurality of trunk cable ports, each of the trunk cable ports receiving a respective one of the set of optical fibers at their transceiver ends; one of the substantially identical transition devices being connected to one end of the trunk cables via its trunk end terminals (902, 903, 804, 806) and the other one of the substantially identical transition devices being connected to the opposite end of the trunk cables via its trunk end terminals (902', 903', 804', 806'); wherein the transition devices (900, 900'; 800, 800') are configured such that the order of optical fibers within the trunk end terminals (902, 902', 903, 903'; 804, 804', 806, 806') and the order of the trunk end terminals (902, 902', 903, 903'; 804, 804', 806, 806') with respect to each other within both transition devices are arranged to produce a mirror image pattern of symmetry, the symmetry being achieved when transmitting fibers and corresponding receiving fibers are located in their respective mirror image positions about the centerline of a generally horizontally arranged array of the trunk end terminations; wherein the system further comprises transceivers connected to the transition device transceiver end terminals on opposite ends of the system. at least two trunk cables (920, 920'; 820, 820') comprising at least four optical fibers and terminals (922, 922', 924, 924'; 822, 822', 824, 824') at opposite ends of the fibers, the terminals (922, 922', 924, 924'; 822, 822', 824, 824') including a plurality of ports, each of the optical fibers being associated with a respective one of the trunk terminal ports; and two substantially identical transition devices (900, 900'; 800, 800'), each of the transition devices (900, 900'; 800, 800') comprising: a first set of at least four optical fibers, each of the optical fibers having a trunk end and a transceiver end; a single transceiver end terminal (904, 904'; 802, 802') having a plurality of transceiver ports, each port connected with a respective one of the set of optical fibers at its transceiver end, wherein a first axis of symmetry divides the ports; a plurality of trunk end terminals (902, 902', 903, 903'; 804, 804', 806, 806'), each of the trunk end terminals (902, 902', 903, 903'; 804, 804', 806, 806') having a plurality of trunk cable ports, each of the trunk cable ports receiving a respective one of the set of optical fibers at their transceiver ends; a first set of at least four optical fibers, each of the optical fibers having a trunk end and a transceiver end; a single transceiver end terminal (904, 904'; 802, 802') having a plurality of transceiver ports, each port connected with a respective one of the set of optical fibers at its transceiver end, wherein a first axis of symmetry divides the ports; a plurality of trunk end terminals (902, 902', 903, 903'; 804, 804', 806, 806'), each of the trunk end terminals (902, 902', 903, 903'; 804, 804', 806, 806') having a plurality of trunk cable ports, each of the trunk cable ports receiving a respective one of the set of optical fibers at their transceiver ends;