A cable backplane system, for connecting a plurality of plug-in cards in a communication device, comprising: a frame; and a cable unit, comprising: a first connector array, fixed on the frame and comprising a plurality of first connectors arranged in rows and columns, wherein the first connectors in the first connector array are connected with first plug-in cards of the plug-in cards, and a respective row of first connectors in the first connector array are connected with a corresponding first plug-in card of the first plug-in cards; a second connector array, fixed on the frame and comprising a plurality of second connectors arranged in rows and columns, wherein the second connectors in the second connector array are connected with second plug-in cards of the plug-in cards, and a respective column of second connectors in the second connector array are connected with a corresponding second plug-in card of the second plug-in cards; and communication cables, wherein each of the communication cables connects one of the first connectors in the first connector array and a corresponding second connector of the second connectors in the second connector array, the system characterized in that the second connector array comprises base columns and extension columns, the base columns indicate columns of the second connector array of which the number is equal to the number of columns of the first connector array, and the extension columns indicate other columns of the second connector array than the base columns, the communication cables comprises a first cable group and a second cable group, when first connectors in a row are respectively connected with second connectors in another row, the first connectors are connected with second connectors in the base columns via the cables in the first cable group and connected with second connectors in the extension columns via the cables in the second cable group. a frame; and a cable unit, comprising: a first connector array, fixed on the frame and comprising a plurality of first connectors arranged in rows and columns, wherein the first connectors in the first connector array are connected with first plug-in cards of the plug-in cards, and a respective row of first connectors in the first connector array are connected with a corresponding first plug-in card of the first plug-in cards; a second connector array, fixed on the frame and comprising a plurality of second connectors arranged in rows and columns, wherein the second connectors in the second connector array are connected with second plug-in cards of the plug-in cards, and a respective column of second connectors in the second connector array are connected with a corresponding second plug-in card of the second plug-in cards; and communication cables, wherein each of the communication cables connects one of the first connectors in the first connector array and a corresponding second connector of the second connectors in the second connector array, the system characterized in that the second connector array comprises base columns and extension columns, the base columns indicate columns of the second connector array of which the number is equal to the number of columns of the first connector array, and the extension columns indicate other columns of the second connector array than the base columns, the communication cables comprises a first cable group and a second cable group, when first connectors in a row are respectively connected with second connectors in another row, the first connectors are connected with second connectors in the base columns via the cables in the first cable group and connected with second connectors in the extension columns via the cables in the second cable group. a first connector array, fixed on the frame and comprising a plurality of first connectors arranged in rows and columns, wherein the first connectors in the first connector array are connected with first plug-in cards of the plug-in cards, and a respective row of first connectors in the first connector array are connected with a corresponding first plug-in card of the first plug-in cards; a second connector array, fixed on the frame and comprising a plurality of second connectors arranged in rows and columns, wherein the second connectors in the second connector array are connected with second plug-in cards of the plug-in cards, and a respective column of second connectors in the second connector array are connected with a corresponding second plug-in card of the second plug-in cards; and communication cables, wherein each of the communication cables connects one of the first connectors in the first connector array and a corresponding second connector of the second connectors in the second connector array, the system characterized in that the second connector array comprises base columns and extension columns, the base columns indicate columns of the second connector array of which the number is equal to the number of columns of the first connector array, and the extension columns indicate other columns of the second connector array than the base columns, the communication cables comprises a first cable group and a second cable group, when first connectors in a row are respectively connected with second connectors in another row, the first connectors are connected with second connectors in the base columns via the cables in the first cable group and connected with second connectors in the extension columns via the cables in the second cable group.