Communication device and communication system

A communication device connected in a ring shape via a communication path, together with a host controller and a plurality of devices, the communication device comprising:

• a receiving circuitry configured to receive from the communication path a communication frame of a serial signal including a plurality of containers including a first container;
• a first circuitry configured to be capable of executing insertion and extraction of data for at least one of the plurality of containers;
• a memory device connected to the first circuitry and configured to store data;
• and
• a transmitting circuitry configured to transmit to the communication path the communication frame based on a processing result of the first circuitry, wherein
• each of the plurality of containers is capable of transferring a copy command, a transmission destination that is a copy source of the copy command, and a copy destination of the copy command, and
• after the receiving circuitry receives a first communication frame including the first container that includes the communication device as a transmission destination and includes the copy command,
• the first circuitry is configured to read out first data stored in the memory device, and
• the transmitting circuitry is configured to transmit a second communication frame including as the transmission destination a first device that is the copy destination among the plurality of devices, and including second data requesting that the read-out first data be written to the first device.

A communication device connected in a ring shape via a communication path, together with a host controller and a plurality of devices, the communication device comprising:

• a receiving circuitry configured to receive from the communication path a communication frame of a serial signal including a plurality of containers including a first container;
• a first circuitry configured to be capable of executing insertion and extraction of data for at least one of the plurality of containers;
• and
• a memory device connected to the first circuitry and configured to store data, wherein
• each of the plurality of containers is capable of transferring a disconnection command to disconnect a connection to the memory device, and
• after the receiving circuitry receives a first communication frame including the first container that includes the communication device as a transmission destination and includes the disconnection command,
• the first circuitry is configured to logically disconnect a connection between the first circuitry and the memory device, based on the disconnection command.