A communication system comprising: a connector (40A, 40B); a master device; a superordinate trunk cable (21A, 21B) connected to the master device; a superordinate slave device (30#1) connected to the master device via the superordinate trunk cable (21A, 21B) and the connector (40A, 40B); a subordinate trunk cable (22A, 22B) connected to the connector (40A, 40B); and a subordinate slave device (30#2) connected to the superordinate slave device (30#1) via the subordinate trunk cable (22A, 22B) and the connector (40A, 40B), the connector (40A, 40B) comprising: a superordinate power line (41A, 41B) via which power that is supplied from the master device is transmitted, a power branching unit (45A, 45B) configured to branch power supplied from the master device into a first power line (41A1, 41B1) toward the superordinate slave device (30#1) and a second power line (41A2, 41B2) toward the subordinate slave device (30#2); a superordinate signal line (43A, 43B) via which communication between the master device and the superordinate slave device (30#1) is transmitted; and a subordinate signal line (44A, 44B) which is insulated from the superordinate signal line (43A, 43B) and via which communication between the superordinate slave device (30#1) and the subordinate slave device (30#2) is transmitted; wherein the master device is a servo amplifier, and each of the superordinate slave device (30#1) and the subordinate slave device (30#2) is any one of an encoder and a sensor. a connector (40A, 40B); a master device; a superordinate trunk cable (21A, 21B) connected to the master device; a superordinate slave device (30#1) connected to the master device via the superordinate trunk cable (21A, 21B) and the connector (40A, 40B); a subordinate trunk cable (22A, 22B) connected to the connector (40A, 40B); and a subordinate slave device (30#2) connected to the superordinate slave device (30#1) via the subordinate trunk cable (22A, 22B) and the connector (40A, 40B), the connector (40A, 40B) comprising: a superordinate power line (41A, 41B) via which power that is supplied from the master device is transmitted, a power branching unit (45A, 45B) configured to branch power supplied from the master device into a first power line (41A1, 41B1) toward the superordinate slave device (30#1) and a second power line (41A2, 41B2) toward the subordinate slave device (30#2); a superordinate signal line (43A, 43B) via which communication between the master device and the superordinate slave device (30#1) is transmitted; and a superordinate power line (41A, 41B) via which power that is supplied from the master device is transmitted, a power branching unit (45A, 45B) configured to branch power supplied from the master device into a first power line (41A1, 41B1) toward the superordinate slave device (30#1) and a second power line (41A2, 41B2) toward the subordinate slave device (30#2); a superordinate signal line (43A, 43B) via which communication between the master device and the superordinate slave device (30#1) is transmitted; and a subordinate signal line (44A, 44B) which is insulated from the superordinate signal line (43A, 43B) and via which communication between the superordinate slave device (30#1) and the subordinate slave device (30#2) is transmitted; wherein the master device is a servo amplifier, and each of the superordinate slave device (30#1) and the subordinate slave device (30#2) is any one of an encoder and a sensor.