Power line communication modem capable of simultaneously supplying power and exchanging data

A power line communication MODEM includes a rectification circuit for converting an AC power source to a DC power source, a MODEM circuit to which a DC voltage is supplied from the rectification circuit, a USB connector connected to the MODEM circuit, and a signal overlapping circuit for overlapping a signal processed by the MODEM circuit with the AC power source, wherein the rectification circuit supplies the DC voltage to the USB connector.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a power line communication MODEM for transferring data from an information processing unit such as a personal computer through a power line.

2. Description of the Related Art

A power line communication MODEM (abbreviated as “PLC MODEM”) is known as means that makes it possible to use a power line such as a distribution line for supplying power from a substation to each home and interior wiring extended in each home as a communication line. The PLC MODEM converts digital data from an information processing unit such as a personal computer to analog line data, overlaps the analog line data with a power line of a commercial power source, or converts the analog line data inputted through the power line to digital signals and transfers them to the information processing unit. Therefore, the PLC MODEM can constitute a communication network among information processing units.

FIG. 3shows a PLC MODEM according to the prior art and a connection diagram when a communication network is constituted by use of the PLC MODEM. This PLC MODEM40includes a power source unit (AC adaptor)41having an attachment plug41awith an AC cord fitted thereto, a MODEM main body unit42and a DC cord43for connecting the power source unit41to the MODEM main body unit42. The power source unit41has a rectification circuit (not shown) for converting a commercial AC power source to a DC power source, and a DC voltage is supplied to the MODEM main body unit42through the cord43.

The MODEM main body unit42has a rectangular parallelepiped shape, accommodates therein a MODEM circuit (not shown) and includes a connector of a USB standard (called “USB connector”)42afitted to one of its side surfaces. The MODEM circuit converts the digital data inputted from the USB connector42ato the analog line data and overlaps the analog line data with the DC voltage of the DC cord43. The analog line data is further overlapped with the AC power source in the power source unit41.

On the other hand, the DC power source is supplied from a power source unit (AC adaptor)45to an information processing unit44such as a notebook type personal computer. An AC cord45ahaving an attachment plug and a DC cord45bhaving a plug are connected to the power source unit45. A USB connector (not shown) is fitted to the information processing unit44, too. The USB connector42aof the MODEM main body unit42and the USB connector of the information processing unit44are connected to each other through a USB cable46.

In the construction described above, when the digital data is inputted from the information processing unit44to the MODEM main body unit42, the MODEM circuit converts the digital data to the analog line data and overlaps the analog line data with the DC cord43for supplying the DC voltage. The analog line data is sent to the interior wiring through the attachment plug41a. Therefore, data communication can be mutually made with other information processing unit inside the same home through the interior wiring. Mutual communication can also be made with other home through the distribution line.

The PLC MODEM and the information processing unit must always be used as a pair. Therefore, when no more spare plug sockets are available, a plug socket must be secured for the information processing unit used together with that for the PLC modem. Alternatively, another plug socket must be provided for branching the plug socket.

The information processing unit is connected to the PLC MODEM and at the same time, must be connected per se to the power source unit. Therefore, mutual connection gets complicated.

SUMMARY OF THE INVENTION

To eliminate the problem described above, the invention makes it possible to simultaneously accomplish the supply of the power source and the exchange of the data by supplying the AC power source to the PLC MODEM from one plug socket inside home and by merely connecting the PLC MODEM to the information processing unit.

To accomplish this object, the invention provides a power line communication MODEM including a rectification circuit for converting an AC power source to a DC power source, a MODEM circuit to which a DC voltage is supplied from the rectification circuit, a USB connector connected to the MODEM circuit, and a signal overlapping circuit for overlapping a signal processed by the MODEM circuit with the AC power source, wherein the DC voltage is supplied to the USB connector.

A case for accommodating the rectification circuit, the MODEM circuit and the signal overlapping circuit is provided, and the USB connector is fitted to the case.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1is a schematic view showing a PLC MODEM according to the invention and connection when a communication network is constituted by use of the PLC MODEM.FIG. 2is a structural circuit diagram of the PLC MODEM according to the invention. Referring toFIGS. 1 and 2, the PLC MODEM10according to the invention includes a MODEM main body unit11and an AC cord12having an attachment plug for supplying AC power to the MODEM main body11. A case11aof the MODEM main body unit11accommodates a front-end11band a MODEM circuit11c. The MODEM circuit11chas a function of converting digital data from an information processing unit13as an external appliance such as a notebook type personal computer to analog line data and vice versa. A connector of a USB standard (called “USB connector”)11dfor exchanging the digital data with the information processing unit13is fitted into the case11a.

A rectification circuit11b1for converting an AC power source to a DC power source and a signal overlapping circuit11b2for overlapping the analog line data from the MODEM circuit11cwith the AC power source are constituted in the front-end11b. The DC voltage from the rectification circuit11b1is supplied to the MODEM circuit11cand to the USB connector11d. The USB connector11dis connected to the MODEM circuit11c.

Here, when a communication network is constituted by use of the information processing unit13, the attachment plug of the AC cord12is fitted into a plug socket inside home. A USB connector (not shown) fitted to the external information processing unit13and the USB connector11dof the MODEM main body unit11are connected to each other through a USB cable14.

In the construction described above, the DC voltage as the power source is supplied to the information processing unit13through the USB cable14. The digital data outputted from the information processing unit13is inputted to the MODEM circuit11cthrough the USB cable14. The MODEM circuit11cconverts the digital data to the analog line data. The signal overlapping circuit11b2overlaps the analog line data with the AC power source (AC cord12having the attachment plug).

The analog line data inputted from outside through the AC power source is inputted to the MODEM circuit11cthrough the signal overlapping circuit11b2. The digital data converted by the MODEM circuit11cis transferred to the information processing unit13through the USB connector11dand through the USB cable14. Therefore, mutual communication can be made inside the same home or with other home through interior wiring or a distribution line.

The information processing unit13may use a digital camera, a digital video apparatus, etc, besides the notebook type personal computer described above.

As explained above, the power line communication MODEM according to the invention includes the rectification circuit for converting the AC power source to the DC power source, the MODEM circuit to which the DC voltage from the rectification circuit is supplied, the USB connector connected to the MODEM circuit and the signal overlapping circuit for overlapping the signal processed by the MODEM signal with the AC power source, wherein the rectification circuit supplies the DC voltage to the USB connector. Therefore, when the AC power source is supplied from one plug socket inside home to the power line communication MODEM, the power source can be supplied to the external information processing unit through the USB cable connected to the USB connector, and the data can be exchanged with the information processing unit through the USB cable.

The PLC MODEM has the case for accommodating the rectification circuit, the MODEM circuit and the signal overlapping circuit and the USB connector is fitted to this case. Therefore, the construction of the power line communication MODEM can be simplified.