JPH0591057A - Optical communication equipment and method - Google Patents

Abstract

PURPOSE:To send plural signals by optical communication without addition of any special configuration to an information processing unit by obtaining drive power for an optical communication equipment from a transmission electric signal line from the information processing unit directly. CONSTITUTION:A power supply circuit 50 generates operating power of all equipments from a signal line S1 from an information processing unit 20, and a modulation circuit 30 outputs a start signal used for lighting a light emitting element 5 for a prescribed time only at a polarity change of any of the plural signal lines S1 and a modulation signal used to control a luminescent/ nonluminescent light of the light emitting element 5 corresponding to a level of a signal allocated to an allocated division time while one of the signal group S1 is allocated to a time subject to time division for each prescribed time. Upon the detection of the reception of the start signal, a demodulation circuit 40 converts a level of each signal group sent for each succeeding prescribed time division time into a level of a relevant signal and outputs the result.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission section which is connected between an optical communication medium and an information processing apparatus and which modulates an electric signal from the information processing apparatus to convert it into a corresponding optical signal and outputs it to the optical communication medium. The present invention relates to an optical communication device and an optical communication method including a receiving unit that converts a modulated optical signal from the optical communication medium into a corresponding electric signal, demodulates it, and outputs it to the information processing apparatus.

[0002]

2. Description of the Related Art In recent years, an example of an optical communication system in which information is transmitted by an optical signal by connecting an optical fiber cable or the like between devices in place of the conventional electric communication system mainly using a metal conductor cable Is increasing. This is because there are advantages such as being capable of large-capacity communication and being less affected by electromagnetic noise and the like.

Recently, particularly in the field of information transmission between individual information processing devices, for example, a computer and an automatic control device, L
Communication between electronic devices such as an AN node and a terminal device, or a host computer and a terminal computer, and use as a signal transmission means inside each of these devices are being attempted. However, when the signal transmission between the devices or inside the device is directly changed to the optical communication system, one optical communication cable and one dedicated optical communication device must be provided for one signal line.

That is, an electric-optical conversion circuit driving unit for driving the same number of electric-optical conversion circuits as signal lines in response to an electric signal from the processing device, an electric-optical conversion circuit (light emitting element, etc.), An optical-electrical conversion circuit (light receiving element), an amplifier circuit for amplifying a signal from the circuit, and the like are required, and an optical communication device needs a separate drive power source for operating each of the above components. The configuration was such that this power was obtained from a commercial power source.

As a result, it is inevitable that the structure will be very large, and in particular, the optical communication cable is expensive and requires skill to be routed, and it is a big problem to have a plurality of cables. Atsuta Therefore, a multiplexing communication method has been proposed in which the number of optical communication cables is reduced, and a plurality of signals are multiplexed and transmitted by, for example, time division transmission.

However, in the conventional multiplexed optical communication method, the communication time is simply time-divided, the signal lines corresponding to the respective divided times are assigned, and the signal level of the corresponding signal line is assigned during the assigned time. Then, whether or not the light emitting means is caused to emit light is controlled. Therefore, every time the time assigned to each signal line comes, the light emission control is always performed according to the signal line level at that time. For example, when the signal is “1”, it is turned on, and when the signal is “0”, it is turned off, and the state of any signal line is constantly transmitted.

That is, for example, if all the signal lines are always "1", the light emitting means is always in the light emitting state.

[0008]

However, it is necessary that the light emitting element, which consumes the most power in the optical communication equipment, always emits light during the pulse duty time of "1" or "0" of the electric signal for input transmission. Therefore, power consumption of several hundred mW to several W was consumed. Therefore, the conventional optical communication device of this type must generate drive power from a commercial power supply. Alternatively, the information processing apparatus needs to have a dedicated AC-DC converter or the like and a separate DC power supply terminal for an optical communication device, which increases the cost of the optical communication device and increases the size of the device. There was a flaw.

[0009]

The present invention has been made for the purpose of solving the above-mentioned problems, and has the following constitution in order to solve the above-mentioned problems. That is, a transmitter connected between the optical communication medium and the information processing device to modulate an electric signal from the information processing device to convert it into a corresponding optical signal and output the optical signal to the optical communication medium, and a modulated optical signal from the optical communication medium. An optical communication device including: a reception unit that converts the signal into a corresponding electric signal, demodulates the signal, and outputs the demodulated signal to the information processing apparatus, wherein the transmission unit receives an electric signal from at least two signal lines from the information processing apparatus. A signal receiving means, a level change detecting means for detecting a level change of the received signal in the electric signal receiving means, and a level change detecting means for detecting each of the received electric signals in the electric signal receiving means when the level change detecting means detects the level change of the signal. A modulation means for expressing each signal state in a time-division manner by outputting a level signal corresponding to the state of the assigned signal for each assigned time, which is a predetermined time for each. An optical-electrical converting means for converting and outputting the modulated electric signal from the modulating means to the optical communication medium as a corresponding optical signal, and the receiving section receives the optical signal from the optical communication medium and converts it into a corresponding electric signal. The optical-electrical converting means, the demodulating means for sampling the electric signal from the optical-electrical converting means at predetermined time intervals and converting into the electric signal of each electric signal level at the time of sampling, and the demodulated signal in the demodulating means. And an output unit for outputting to the information processing device.

For example, it further comprises power generation means for generating drive power for the receiving section and the transmitting section from an electric signal from the connection information processing apparatus.

[0011]

With the above structure, a plurality of signals from the information processing device can be reliably transmitted to the other party in a short light emitting time. For this reason, it becomes possible to obtain the driving power of the optical communication device directly from the electric signal line for transmission from the information processing device, and the status of the plurality of signal lines can be detected without adding any special configuration on the information processing device side. It can be transmitted to the other device by communication.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described in detail below with reference to the drawings. FIG. 1 is a block diagram of an embodiment according to the present invention. In FIG. 1, 1 is an optical communication device,
Reference numerals 8 and 9 denote optical communication connector portions, 10a and 10b denote optical communication fiber cables, and 20 denotes an information processing device.

In the case of two-way optical communication, the signal line group S1 from the information processing device 20 is sent to the modulation circuit 30 via the electric connector 2, the receiver circuit 3a of the interface circuit 3, and the modulation circuit 30 will be described later. It is received and converted into one time-division signal, which is then sent to the drive circuit 4, converted into a corresponding optical signal by the light emitting element 5 and sent out to the optical fiber cable 10a through the optical communication connector section 8 and is sent to the destination. It is transmitted to the light receiving element of the optical communication device.

On the other hand, the optical signal transmitted from the light emitting element of the counterpart optical communication device via the optical fiber cable 10b is received by the light receiving element 7 via the optical communication connector section 9, and the corresponding electric signal is received here. To the demodulation circuit 40 after being amplified by the amplifier circuit 6 and subjected to a demodulation process described later to be converted into a plurality of corresponding signals, and the driver circuit 3b of the interface unit 3 and the electrical connector 2 It is output as a reception signal line group S2 to the information processing device 20 via.

In transmitting and receiving such a signal, all the electric power required to drive each component is supplied from the power supply circuit 50. The signal line group S1 output from the signal output driver circuit (not shown) of the information processing device 20 is also input to the power supply circuit 50, and the power supply circuit 50 outputs the signal line group S.
1 generates + V1 and ± V2 electric power required for optical communication equipment. In the figure, the signal circuit lines are indicated by thin lines, and the power circuit lines are indicated by thick lines for easy explanation.

FIG. 2 shows the detailed configurations of the modulation circuit 30 and the demodulation circuit 40 described above. The modulation circuit 30 has the following configuration. A change in the signal level of the signal line group 44 converted into a signal level that can be processed by the receiver device 3a, that is,
The signals of the signal polarity change detection circuit 31 and the signal line group 44 that detect the rising or falling of each signal are latched under the control of the control circuit A33.
Parallel-serial conversion circuit 32 for converting to serial data and outputting, control circuit A3 for controlling modulation
3, a timer circuit 34 that notifies the elapse of a predetermined time, and an oscillation circuit A35 that constantly oscillates a clock signal of a predetermined frequency,
It is composed of a gate 36. Reference numeral 20 is a clock signal, 21 is a polarity change detection signal, 22 is a shift timing signal, 23 is a modulation signal, and 24 is a transmission permission signal.

The demodulation circuit 40 has the following configuration. A serial modulation electric signal from the control circuit B41, which controls the demodulation, and the amplifier circuit 6, is supplied to the control circuit B4.
A serial-parallel conversion circuit 42 for converting into a corresponding parallel signal under the control of No. 1 and an oscillation circuit B43 for oscillating a clock signal in synchronization with the received signal. 43a is a sampling clock signal, 4
6 is a reception modulation signal, 47 is an oscillation permission signal, 48 is a demodulation signal, and 49 is a shift timing signal. A detailed configuration of the power supply circuit 50 shown in FIG. 1 is shown in FIG.

In FIG. 3, D1 and D2 are rectifying diodes, C1 and C2 are smoothing capacitors, 12 is a voltage regulator, 13 is a DC-DC converter, D3 and D4 are protection diodes, and C3 is a filter capacitor. .. In FIG. 3, the signal line group S1 from the information processing device 20 and the rectifying diodes D1 and D2 are shown as if they were one signal line and one rectifying diode, respectively. This is prevented because the figure becomes complicated by showing the same configuration for multiple lines.
The number of signal lines is not limited to one, and it goes without saying that the number of rectifying diodes is equal to the number of signal lines.

Input from the signal line group S1 from the information processing device 20 through the electric connector 2, and a "+" potential,
The smoothing capacitor C is rectified by the rectifier diodes D1 and D2 provided for each signal line according to the "-" potential.
The ripple components are removed by 1 and C2 and smoothed. Thereafter, the ± V2 power supplies are stabilized and output by the action of the DC-DC converter 13. This ± V2 power supply is supplied to the receiver circuit 3a and the driver circuit 3b of the interface circuit 3.

At the same time, the "+" level input is stabilized by the voltage regulator 12 after the ripple component is removed and smoothed by the smoothing capacitor C1 and + V1 power is supplied. The + V1 power is supplied to the drive circuit 4 including the modulation circuit 30 and the light emitting element 5 of the transmission circuit, and the amplification circuit 6 and the demodulation circuit 40 including the light receiving element 7 of the reception circuit.

Here, the electric power supplied from the stabilized power supply circuit 50 is limited by the supply current of the transmission signal output driver circuit and the control output driver circuit in the connected information processing apparatus 20. For example, when the interface specification is RS-232C specification, TxD,
The required power can be supplied from the RTS, DTR signals and the like.

Further, the voltage regulator 12 and the DC-D
It is necessary to form the C converter 13 of a power consumption type as low as possible, and it is desirable to use a MOS.FET type, and the other circuit portion of this embodiment can have a CMOS gate structure to reduce power consumption. desirable. still,
When more drive power for the light emitting element 5 is required, the voltage regulator 12 may be a highly efficient DC-DC converter.

An example of a detailed circuit diagram of the amplifier circuit 6 of FIG. 1 is shown in FIG.
Shown in. The performance of the amplifier required for the opto-electric conversion unit must be high input impedance, low input capacitance, and have high speed and high stability.
However, the conventional amplifier of this type is not only expensive but also of high power consumption type in order to be a high speed type. Further, the stability is low, and there is a risk of malfunction such as when the emitted light is greatly attenuated. Therefore, in view of the fact that all the driving power of this embodiment must be generated from the signal line to the information processing device, it is a problem to use the conventional type amplifier. For this reason, in this embodiment, the amplifier shown in FIG. 4 is provided, and as is apparent from FIG. 4, general CMOS and IC gates are used for the input stage, and high input impedance and low input capacitance are obtained. Has been realized. Since the gain is insufficient only with the CMOS and IC, a grounded base circuit of a transistor and a constant current load circuit with an FET transistor are further configured, and a second stage is configured with the same configuration and divided into two stages. The required gain is obtained. After the required gain is secured in this way, the waveform shaping circuit 6a shapes the waveform and outputs it as a reception modulation signal. Moreover, with the above configuration, the phase delay due to the circuit is reduced at the same time, and the power consumption is suppressed to the necessary minimum. Therefore, it has a substantially ideal amplifier circuit configuration. The operation of this embodiment having the above configuration will be described below with reference to the timing charts of FIGS. The following explanation is
The output from the information processing device 20 complies with the RS-232C standard, and the output signal group S1 is TxD, DTR,
The case where there are four kinds of signals of RTS and another arbitrary control signal (indicated by "X" in the figure) is taken as an example. However, the output signal group S1 of the present embodiment is not limited to the above example, and even if the configuration receives more various control signal lines, optical communication can be performed by the same control as the control described below. Of course.

An output signal group S output from a driver circuit (signal output IC) (not shown) built in the information processing apparatus 20.
1 is output to the receiver circuit 3a of the interface circuit 3 via the connector 2. At the same time, the output signal group S1 is also input to the power supply circuit 50. First, FIGS.
The control of the transmitter will be described with reference to FIG. FIG. 5 shows the modulation circuit 3
0 is a timing chart inside 0, FIG. 6 is a diagram showing a configuration of a modulation signal of this embodiment, and FIG. 8 is a diagram showing a modulation signal output timing of this embodiment.

Signal group 44 received by the receiver circuit 3a
Is input to the modulation circuit 30. The signal polarity change detection circuit 31 of the modulation circuit 30 constantly monitors whether or not any of the signals of the input signal group 44 rises or falls, that is, whether or not there is a change in the polarity of the output signal from the information processing device 20. is doing. Then, when the fall or rise is detected, the polarity change detection signal 21 is output to the control circuit A33. Actually, the signal polarity change detection circuit 31 is provided with a differentiating circuit for each signal and outputs the polarity change detecting signal 21 having a pulse width determined by the differentiating circuit at the rising or falling edge.

The polarity change detection signal 21 is parallel-
It is also output to the serial conversion circuit 32, and the parallel-
The serial conversion circuit 32 outputs the polarity change detection signal 21 in synchronization with the clock signal 20 from the oscillation circuit A35 which always outputs the clock signal at a constant frequency (1 MHz in this embodiment). First clock signal 2
At the rising timing of 0, the signal group 44 from the receiver circuit 3a is latched. Then, thereafter, the latch data is sequentially shifted out in accordance with the shift timing signal 22 from the control circuit A33. A signal of "1" is always output as the modulation signal 23 while the shift timing signal 22 does not come.

On the other hand, the control circuit A33, which has received the polarity change detection signal 21, receives the polarity change detection signal 21.
The flip-flop of the first stage of the signal input stage is set at the rising timing of. Then, at the rising timing of the clock signal 20 in the state where the flip-flop of the first stage is set, the flip-flop of the second stage is set. The flip-flop of the first stage is reset by the set of the flip-flop of the second stage.
The output of the second flip-flop is the transmission permission signal 2
It becomes 4. At this time, since the modulation signal 23 is "1" as described above, the gate 36 is satisfied and the light emitting element 5 is controlled to the light emitting state. As described above, the flip-flop of the first stage is provided to output the transmission permission signal 24 in order to prevent the polarity change detection signal 21 from being missed when the transmission permission signal 24 is being output. ..

When the flip-flop of the second stage is set, the control circuit A33 outputs the shift timing signal 22 having a predetermined pulse width at each subsequent rising edge of the clock signal 20. In the present embodiment, four types of signals are modulated and output. Therefore, when four shift timing signals 22 are output, the modulation output of all signals ends. Therefore, the data transmission end signal is output at the rising timing of the clock signal after the four shift timing signals 22 are output, the flip-flop of the second stage is reset by the signal, and the transmission permission signal 24 is turned off. As a result, the gate 36 becomes unsatisfied thereafter, and thereafter, the modulation signal 45 is not output until the polarity change detection signal 21 is output again. The above timing is shown in FIG.
Is shown in.

As shown in FIG. 6, the signal 45 thus modulated and output has a structure in which the light emitting element 5 first emits light for one cycle of the clock signal 20, and thereafter, after detecting a change in polarity. The light emission or non-light emission state corresponding to the signal level continues. For example, the first light emission timing is used as a start signal, and thereafter, the transmission timing of TxD, DTR, RTS, and an arbitrary signal (X) is used. When transmitting a larger number of signals, the number of outputs of the shift timing signal 22 in FIG. 5 may be increased.

The output timing of the modulated signal in this embodiment is every timing of the polarity change of any signal of the output signal group S1 as shown in FIG. Therefore, in the present embodiment, the light emission time of the light emitting element 5 can be suppressed to the necessary minimum, and the power consumption can also be suppressed to the minimum. From the above viewpoint, the light emission timing according to the state of the output signal group S1 is, of course, the light emission of the light emitting element 5 at a level at which the light emitting element 5 is unlikely to be turned on during data transmission. As described above, the driving method of the light emitting element 5 which consumes the most power in the optical signal equipment is controlled to emit light in time series for each signal so that the minimum light emitting time is obtained only when the signal polarity changes from the conventional direct luminance modulation method. By doing so, the light emission time of the light emitting element 5 could be reduced to several tenths to several hundredths of that of the conventional method.

The optical signal modulated and emitted as described above is
The light is received by the receiving unit of the optical communication device of the communication partner via the optical fiber cable 10a, demodulated into a corresponding electric signal group, and output to the connection information processing apparatus. In addition to the above transmission timing, the timer circuit 34
This configuration is provided to perform the same modulation signal transmission as in the case where a change in the signal polarity is forcibly detected when no modulation signal is transmitted for a predetermined set time. That is, this is a countermeasure when the partner optical communication device is not in the communication state, and is a configuration provided for smoothly performing the handshake when the partner optical communication device is in the communication enabled state. The operation of the receiving unit that receives the modulated signal of the above specifications sent from the partner optical communication device via the optical fiber cable 10b will be described below with reference to the timing chart of FIG.

The optical signal sent from the other party's optical communication device via the optical fiber cable 10b is a modulated signal modulated by the same method as described above. In the receiving side circuit, from the light emitting element of the other party's optical communication device to the optical fiber cable 10
b, the optical signal modulated and transmitted in the same manner as in the case of the above-mentioned transmission sent via the connector 9 is received by the light receiving element 7 and is optically-electrically converted. This converted electrical signal is shown in FIG.
The signal is amplified by the amplifier circuit 6 shown in (4) and input to the demodulation circuit 40 as a highly reliable binary modulation signal 46 similar to that on the transmitting side.

Control circuit B41 of demodulation circuit 40
Monitors the reception modulation signal 46, and when the optical signal is received, at the rising timing of the reception modulation signal 46, an oscillation permission flip-flop (not shown) is set and an oscillation permission signal 47 is output. When the serial-parallel conversion circuit 42 receives the shift timing signal 49 while the oscillation permission signal 47 is being output, the input modulation signal 46 is received.
Are taken in by the shift register section and sequentially shifted.

On the other hand, when the oscillation enable signal 47 is set, the oscillator circuit B43 starts the clock oscillation in synchronization with the rising of the oscillation enable signal. This oscillator circuit B4
The oscillation frequency of No. 3 is substantially the same as that of the oscillation circuit A35. The control circuit B41 generates a sampling clock 2 signal having a phase difference of 180 degrees from the sampling clock signal 43a from the oscillation circuit B43, and if the reception modulation signal 46 is still on at the rising timing of the signal, the internal shift timing is changed. The clock control control signal that permits the output of the signal is turned on. If the reception modulation signal 46 is not turned on at the rising timing of this signal, it is determined that the previous detection is erroneous, the control control signal is not output, and the oscillation permission signal 47 described above is reset. As a result, the operation of the receiver is stopped.

If this is not the case, the control control signal is set, and a shift timing signal having a predetermined pulse width is sequentially output to the serial-parallel conversion circuit 42 at each rising timing of the subsequent sampling clock 2 signal. When four are output, a data set signal is output, the shift data at that point in the shift register section of the serial-parallel conversion circuit 42 is latched in the latch section, and is output to the driver circuit 3b as an output signal group 48. .. At the same time, the oscillation enable signal 47 is reset by the data set signal, the received modulated signal 46 is demodulated, and the operation is stopped in the state where it is latched by the latch section. Then, it waits for reception of the next start signal. In this case, as shown in FIG. 8, the first shift timing signal is output at a timing just after the start signal reception timing, which is just in the middle of the first transmission signal, for example, TxD reception timing. Therefore, the received modulated signal can be demodulated.

As described above, in the receiving section of the present embodiment, the oscillation of the sampling clock is started at the timing when the start signal is received. Therefore, the sampling timing is set to the timing with the least erroneous sampling with a simple configuration and control. be able to. Then, the demodulated electric signal 48 is output to the information processing device 20 as a signal group S2 via the driver circuit 3b of the interface circuit 3 and the connector 2.

As described above, according to the present embodiment, the time-division modulation / demodulation method is adopted as the signal driving method to reduce the driving power of the light emitting element 5, and the driving power of the optical communication device is changed to the optical communication. Since it is possible to obtain it from the electric signal input to the equipment, it is not necessary to receive a separate power source from the outside, power supply equipment is not required, and the electrical power via the existing metal conductor is eliminated. It becomes possible to perform optical communication with a device having a different communication control configuration.

As described above, the cost reduction, the size reduction, and the power saving of the optical communication device are achieved, and the effect of contributing to the industry is extremely great.

[0039]

As described above, according to the present invention, it is possible to modify an apparatus having an electrical communication control configuration through an existing metal conductor without making any changes and adding any special configuration. It becomes possible to communicate. Further, it is possible to provide a highly reliable device that consumes less power and can minimize transmission errors.

[Brief description of drawings]

FIG. 1 is a block diagram of an optical communication device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a detailed configuration of a modulation circuit and a demodulation circuit shown in FIG.

3 is a diagram showing a detailed configuration of a power supply circuit 50 shown in FIG.

FIG. 4 is a detailed circuit diagram of the amplifier circuit shown in FIG.

FIG. 5 is a diagram showing a modulated signal transmission timing of the present embodiment.

FIG. 6 is a diagram showing a configuration of a modulation signal of the present embodiment.

FIG. 7 is a diagram showing a modulation signal output timing of the present embodiment.

FIG. 8 is a diagram showing a reception modulation signal demodulation timing of the present embodiment.

[Explanation of symbols]

 1 optical communication equipment, 2 electrical connection connector, 3 interface circuit, 3a receiver circuit, 3b driver circuit, 4 drive circuit, 5 light emitting element, 6 amplification circuit, 7 light receiving element, 8, 9 optical communication connector section, 10a, 10b Fiber cable for optical communication, 12 Regulator, 13 DC-DC converter, 20 Information processing device, 30 Modulation circuit, 31 Signal polarity change detection circuit, 32 Parallel-serial conversion circuit, 33,41 Control circuit, 35,43 Oscillation circuit , 40 demodulation circuit, 42 serial-parallel conversion circuit, 50 power supply circuit.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location 8020-5K H04L 13/00 T

Claims (5)

[Claims] 1. A transmission unit connected between an optical communication medium and an information processing apparatus, which modulates an electric signal from the information processing apparatus to convert the signal into a corresponding optical signal and outputs the corresponding optical signal to the optical communication medium; An optical communication device comprising: a reception unit that converts the modulated optical signal of 1 to a corresponding electric signal, demodulates it, and outputs the demodulated optical signal to the information processing device, wherein the transmission unit is at least two signal lines from the information processing device. An electric signal receiving means for receiving each electric signal,
Level change detecting means for detecting a level change of the received signal in the electric signal receiving means, and for each received electric signal in the electric signal receiving means when the level change detecting means detects the level change of the signal A modulation means for expressing each signal state in a time-division manner by outputting a level signal corresponding to the state of the allocation signal for each predetermined allocation time during each allocation time, and an optical signal corresponding to the modulated electric signal from the modulation means. An optical-electrical converting means for converting and outputting to the optical communication medium as a signal, wherein the receiving section receives an optical signal from the optical communication medium and converts it to a corresponding electric signal; and Light-
Demodulation means for sampling the electric signal from the electric conversion means at predetermined time intervals and converting it to an electric signal of each electric signal level at the time of sampling, and output means for outputting the demodulated signal by the demodulation means to the information processing device. An optical communication device comprising: 2. The optical communication device according to claim 1, further comprising power generation means for generating drive power for the receiver and the transmitter from an electrical signal from the connection information processing device. .. 3. The modulator means time-divisionally processes each electric signal level received by the electric signal receiving means following a start signal indicating the start of optical communication of a predetermined time width, and the time-series electric signal having the predetermined time width. The signal level is converted into a signal level, and the demodulation means detects the reception of an optical signal indicating the start of optical communication within a predetermined time width and samples the reception signal level of the reception signal received in time series within the subsequent predetermined time width. The optical communication device according to claim 1 or 2, wherein the optical signal is output as a corresponding electrical signal for each sampling. 4. The optical communication, which is connected between the optical communication medium and the information processing apparatus, modulates at least two kinds of electric signals from the information processing apparatus and converts them into corresponding optical signals, and outputs them to the optical communication medium. An optical communication method in an optical communication device for converting a modulated optical signal from a medium into a corresponding electric signal and demodulating and outputting the electric signal to the information processing apparatus, wherein one of the signal lines of the signal line from the information processing apparatus When a change in the signal level is detected, a start signal having a predetermined time width is generated, and a predetermined time is allocated to each of the reception signals from the information processing device, once for the generated start signal. In particular, a time series signal corresponding to the state of the allocation signal is generated, and the start signal and the generated time series signal are converted and output as the corresponding optical signals to the optical communication medium. Optical communication method to be. 5. The optical communication method according to claim 4, wherein when an optical signal corresponding to a start signal having a predetermined time width is received from the optical communication medium, the optical signal intensity for each predetermined time width is sent following the light reception. Is detected, converted into a signal level for each signal line allocated for each time, and output to the information processing device.