A transmission device comprising: a first signal processing unit that is configured to perform, as processing of a first layer, processing of generating a packet that stores data to be transmitted and distributing the packet that has been generated to a plurality of lanes; and a second signal processing unit that is configured to perform, as processing of a second layer, processing including insertion of control information in parallel on the packet of each of the lanes output from the first signal processing unit, and processing of outputting a data stream obtained by performing the processing onto a transmission line to a reception device, wherein the first signal processing unit and the second signal processing unit are configured to input and output signals according to specifications of input and output defined on a basis of the first layer and specifications of input and output defined on a basis of the second layer, wherein the first signal processing unit and the second signal processing unit are provided respectively on different integrated circuit chips, the transmission device being characterized in that: the first signal processing unit is configured to perform processing of the first layer according to one of a scalable low voltage signaling-embedded clock standard or another transmission standard, while the second signal processing unit is configured to perform processing of the second layer according to the other one of the scalable low voltage signaling-embedded clock standard or the other transmission standard. a first signal processing unit that is configured to perform, as processing of a first layer, processing of generating a packet that stores data to be transmitted and distributing the packet that has been generated to a plurality of lanes; and a second signal processing unit that is configured to perform, as processing of a second layer, processing including insertion of control information in parallel on the packet of each of the lanes output from the first signal processing unit, and processing of outputting a data stream obtained by performing the processing onto a transmission line to a reception device, wherein the first signal processing unit and the second signal processing unit are configured to input and output signals according to specifications of input and output defined on a basis of the first layer and specifications of input and output defined on a basis of the second layer, wherein the first signal processing unit and the second signal processing unit are provided respectively on different integrated circuit chips, the transmission device being characterized in that: the first signal processing unit is configured to perform processing of the first layer according to one of a scalable low voltage signaling-embedded clock standard or another transmission standard, while the second signal processing unit is configured to perform processing of the second layer according to the other one of the scalable low voltage signaling-embedded clock standard or the other transmission standard. the first signal processing unit is configured to perform processing of the first layer according to one of a scalable low voltage signaling-embedded clock standard or another transmission standard, while the second signal processing unit is configured to perform processing of the second layer according to the other one of the scalable low voltage signaling-embedded clock standard or the other transmission standard.