A line concentrator adapted to be inserted into a connector on a motherboard, comprising: a body, comprising a plurality pairs of sidewalls connected to each other and a bottom plate connected to the sidewalls, wherein the sidewalls of each pair are opposite to each other, the sidewalls surround and define an accommodating cavity configured to receive a signal cable connector therein, and the bottom plate comprises a plurality of holes communicated with the accommodating cavity; and at least one arm, protruding from one of the sidewalls of one of the pairs and extending along a direction away from the bottom plate, wherein the at least one arm protrudes over the sidewalls and comprises at least one position limiting protrusion, and the at least one position limiting protrusion protrudes toward the opposite one of the sidewalls of one of the pairs and is located directly above the accommodating cavity; wherein the bottom plate includes a first surface and a second surface opposite to the first surface, each of the holes is respectively perforated through the first surface and the second surface, each of the holes is defined by a surrounding sidewall, a periphery of the surrounding sidewall at the second surface is larger than a periphery of the surrounding sidewall at the first surface; and wherein the first surface is a top surface of the bottom plate, and the second surface is a bottom surface of the bottom plate; characterized in that the surrounding sidewall is inclined from the first surface toward the second surface thereby guiding pins inside the connector on the motherboard so that a positional deviation of the signal line cable connector can be compensated. a body, comprising a plurality pairs of sidewalls connected to each other and a bottom plate connected to the sidewalls, wherein the sidewalls of each pair are opposite to each other, the sidewalls surround and define an accommodating cavity configured to receive a signal cable connector therein, and the bottom plate comprises a plurality of holes communicated with the accommodating cavity; and at least one arm, protruding from one of the sidewalls of one of the pairs and extending along a direction away from the bottom plate, wherein the at least one arm protrudes over the sidewalls and comprises at least one position limiting protrusion, and the at least one position limiting protrusion protrudes toward the opposite one of the sidewalls of one of the pairs and is located directly above the accommodating cavity; wherein the bottom plate includes a first surface and a second surface opposite to the first surface, each of the holes is respectively perforated through the first surface and the second surface, each of the holes is defined by a surrounding sidewall, a periphery of the surrounding sidewall at the second surface is larger than a periphery of the surrounding sidewall at the first surface; and wherein the first surface is a top surface of the bottom plate, and the second surface is a bottom surface of the bottom plate; characterized in that the surrounding sidewall is inclined from the first surface toward the second surface thereby guiding pins inside the connector on the motherboard so that a positional deviation of the signal line cable connector can be compensated.