Communication device and communication system

A communication device, comprising:

• a receiver configured to receive a data signal, the receiver including an input level monitor configured to measure an input level of the data signal;
• a controller configured to generate an optical transmission stop instruction;
• and
• a transmitter configured to receive the optical transmission stop instruction from the controller and transmit the optical transmission stop instruction to an external device via an electrical wire,
• wherein the optical transmission stop instruction has a predetermined bit pattern and includes a packet body, and
• wherein, in a case where the input level is below a threshold level, the receiver is configured to cause the controller to generate the optical transmission stop instruction.

A communication system, comprising:

• a first communication device, including:
• a first transmitter configured to generate a first data signal, the first transmitter including a drive current monitor configured to detect a drive current of an optical transmitter coupled to the transmitter,
• a first controller configured to stop an operation of the first transmitter in response to an optical transmission stop instruction, and
• a first receiver configured to receive the optical transmission stop instruction via an electrical wire, and output the optical transmission stop instruction to the first controller;
• a second communication device, including:
• a second receiver configured to receive a second data signal;
• and
• a transmission cable including the electrical wire and at least one optical fiber,
• wherein the optical transmission stop instruction has a predetermined bit pattern and includes a packet body,
• wherein the first receiver is configured to receive the optical transmission stop instruction from the second communication device, and
• wherein, in a case where the drive current monitor detects that the drive current exceeds a threshold current, the first transmitter is configured to output the optical transmission stop instruction to the first controller.

A communication method, comprising:

• generating, at a first communication device, a first data signal;
• detecting, at the first communication device, a drive current of an optical transmitter of the first communication device;
• generating, at a second communication device optically coupled to the first communication device, a second data signal based on the first data signal;
• receiving, at the first communication device, an optical transmission stop instruction from the second communication device via an electrical wire;
• in a case where the detected drive current exceeds a threshold current, outputting the optical transmission stop instruction to a controller of the first communication device;
• and
• in response to the optical transmission stop instruction, stopping the generating of the first data signal,
• wherein the optical transmission stop instruction has a predetermined bit pattern and includes a packet body.