JPH0364899B2 - - Google Patents

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to a local area network system that enables communication between information processing devices such as personal computers, and particularly relates to a local area network system that enables communication between information processing devices such as personal computers, and in particular, to The present invention relates to a printer sharing system for sharing printers via a printer.

[Technical Background of the Invention] Generally, a personal computer has a built-in printer interface so that it can be connected to a printer. Therefore, by connecting a printer to a personal computer, print data from the personal computer can be directly printed out from the printer. However, the method of connecting a printer to each personal computer is wasteful if the printer is used infrequently. Therefore, as shown in Figures 2 and 3, 1
A system has been developed in which a single printer is shared by multiple personal computers.

In the system shown in FIG. 2, a plurality of personal computers (PCs) 12 share one printer 13 by switching a changeover switch 11. The system shown in Fig. 3 uses a local area network (hereinafter referred to as LAN), and the personal computer 21 is connected to the LAN.
By connecting the adapter 22 to a LAN cable 23, communication between the personal computers 21 is possible. In the system shown in FIG. 3, the printer 23 is connected to the LAN cable 22 by the printer server 24, and printer data is transmitted from the personal computer 21 to the printer server 24 in the same manner as in the case of communication between the personal computers 21.
It is possible to print out the image from the printer 23.

[Problems with Background Art] However, the system shown in FIG. 2 has a problem in that the installation range and number of personal computers 12 that share the printer 13 are limited due to limitations on printer cable length and the like.

Furthermore, although the system shown in FIG. 3 does not have the same limitations as the system shown in FIG. 3 and allows communication between the personal computers 21, it has the following problems. In other words, in the system shown in Figure 3, the LAN
The interface of the personal computer 21 connected to the LAN cable 23 by the adapter 22 is a communication interface such as RS232C, which is different from a printer interface (generally a Centronics interface) to which a printer can be directly connected. Therefore, the personal computer 21 connects to the printer 23 via the LAN.
To use the personal computer 2
It is necessary to change the printer connection program originally included in the printer 1 so that it can output printer data from the communication interface.

[Purpose of the Invention] This invention was made in view of the above circumstances, and its purpose is to provide a local printer that allows printers within a system to be shared without changing the printer connection program originally included in information processing equipment such as a personal computer. Its purpose is to provide an area network system.

[Summary of the Invention] In the present invention, a local area network adapter is provided for connecting information processing equipment to a local area network. This adapter includes
A second communication interface compatible with the first communication interface of the information processing device and a local area network controller for controlling data transmission and reception with the local area network are provided. The adapter is also provided with a second printer interface compatible with the first printer interface of the information processing device, and the print data generated by the processing device is transferred to the second printer via the first printer interface. The information is received at the interface and sent to the printer server connected to the local area network under transmission control of the local area network controller in the adapter.

[Embodiment of the Invention] FIG. 1a shows the configuration of a LAN (Local Area Network) system according to an embodiment of the present invention, and 30 is a LAN cable (communication cable) such as a coaxial cable. 31a to 31d are information processing devices, such as personal computers;
2a is a personal computer 31a, 31b.
LAN adapter connected to LAN cable 30, 3
2b has personal computers 31c and 31d.
This is a LAN adapter connected to the LAN cable 30. 33 is a printer, 34 is a printer 33
This is a printer server connected to a LAN cable 30.

41a and 41b are personal computers 31
Connect a, 31b and LAN adapter 32a
Interface cables such as RS232C cables,
41c and 41d are personal computers 31
This is an interface cable similar to the cables 41a and 41b that connect the cables 41a and 31d and the LAN adapter 32b. 42a, 42b are personal computers 31a, 31b and LAN adapter 32
Interface cable such as Centronics interface cable connecting a, 42c, 4
2d is a personal computer 31c, 31d and
Cable 42 connecting with LAN adapter 32b
This is an interface cable similar to a and 42b. 43 is a printer 33 and a printer server 3
This is an interface cable similar to the cables 42a to 42d that connect the terminals 4 to 4.

Figure 1b shows the LAN adapter 32 shown in Figure 1a.
The configuration of a (32b) is shown. 51a, 51b (51
c, 51d) are personal computers 31a,
This is a serial input/output controller (SIO) that is compatible with the serial interface (communication interface) 61a, 61b (61c, 61d) that is equivalent to RS232C that the 31b (31c, 31d) has. ) and interface cables 41a, 41b (41c,
41d). 52a, 52b
(52c, 52d) is personal computer 3
This printer interface is compatible with printer interfaces 62a, 62b (62c, 62d) equivalent to Centronics interfaces possessed by 1a, 31b (31c, 31d), and interface cable 42a with interfaces 62a, 62b (62c, 62d). , 42b (42c, 42
d).

53 is a LAN controller that controls data transmission to the LAN cable 30 and data reception from the LAN cable 30, and 54 is a memory that stores data. 55 is the LAN adapter 32a (3
2b) Microprocessor that controls the whole, 56
is an internal bus.

Next, the operation of the above configuration will be explained.

First, regarding communication between personal computers, a case will be described in which data is transferred from the personal computer 31a to the personal computer 31c. In this case, the personal computer 31a transfers the address information of the other personal computer 31c according to the format instructed by the LAN adapter 32a from its serial interface 61a to the LAN adapter 32a (to its serial input/output controller 51a) via an interface cable. 41a as serial data.
The serial input/output controller 51a in the LAN adapter 32a transfers serial data from the personal computer 31a to the interface cable 41.
When received from a, the same serial data is converted into parallel data. Next, the series input/output controller 5
1a interrupts the microprocessor 55 via the internal bus 56 to indicate that data is available. As a result, the microprocessor 55 receives data (parallel data indicating the other party's address) from the serial input/output controller 51a via the internal bus 56.

When the microprocessor 55 in the LAN adapter 32a receives the destination address transferred from the personal computer 31a, it transfers the data to the personal computer 31c indicated by the same address.
is connected to the LAN adapter 32b.
A connection request is made via the controller 53 and the LAN cable 30. Data transfer methods on this LAN cable 30 include CSMA/CD method,
Alternatively, a well-known method such as a token method is applied, so a detailed explanation will be omitted.

Now, LAN adapter 32b is LAN adapter 3
Upon receiving the connection request from 2a, the personal computer 51c connects to the personal computer 51a.
If it is possible to receive data from the server, it responds that it is possible to connect. This enables the personal computer 31a to send data, and in turn transfers data to the personal computer 31c from its serial interface 61a.
The data is transferred as serial data to (the serial input/output controller 51a of) the LAN adapter 32a via the interface cable 41a. This serial data is converted into parallel data by the serial input/output controller 51a. LAN adapter 32a
The microprocessor 55 in the
Parallel converted data to serial input/output controller 5
1d via internal bus 56 and memory 54
Temporarily stored in . and microprocessor 55
requests the LAN controller 53 to send data.

LAN controller 5 in LAN adapter 32a
3 generates a transmission packet containing data (from the personal computer 31a) stored in the memory 54 in response to a transmission request from the microprocessor 55, and sends it to the other party via the LAN cable 30.
It is sent to the LAN adapter 32b.

LAN controller 5 in LAN adapter 32b
3 is LAN transmitted via LAN cable 30
Receives packets from adapter 32a and connects to LAN
It is temporarily stored in the memory 54 in the adapter 32b.
When the LAN controller 53 finishes receiving the packet, it sends a message to that effect to the microprocessor 55.
to notify. As a result, the microprocessor 55 in the LAN adapter 32b retrieves the data temporarily stored in the memory 54 and transfers it via the internal bus 56 to the serial input/output controller 51c.
When the serial input/output controller 51c receives data from the microprocessor 55, it converts the data into serial data and sends it to the interface 41c.
The data is then transferred to (the serial interface 61c of) the personal computer 31c. As described above, data is transferred from the personal computer 31a to the personal computer 31c.

Next, a case will be described in which print data is transferred from the personal computer 31a to the printer server 34. In this case, the personal computer 31a has its printer interface 6.
2a outputs data to the LAN adapter 32a (internal printer interface 52a) via the interface cable 42a, using exactly the same procedure as when a printer is directly connected to the LAN adapter 32a. The printer interface 52a in the LAN adapter 32a is connected to the personal computer 31a.
When viewed from the computer 31a, it receives data from the computer 31a as if it were a printer,
The microprocessor 55 is notified of this fact. As a result, the microprocessor 55 in the LAN adapter 32a transfers the data received by the printer interface 52a to the memory 54 via the internal bus 56.
Temporarily stored in . and microprocessor 55
requests the LAN controller 53 to send data.

LAN controller 5 in LAN adapter 32a
3 generates a transmission packet containing the print data (from the personal computer 31a) stored in the memory 54 in response to a transmission request from the microprocessor 55, and transmits it to the printer server 34 via the LAN cable 30. When the printer server 34 receives the packet from the LAN adapter 32a, it outputs the print data in the packet to the printer 33. As described above, the personal computer 31a can output print data to the printer server 34 in the LAN system. Note that the personal computer 31b
It is clear that the computers 31d to 31d can also output print data to the printer server 34 in the same way as the personal computer 31a.

In the above embodiment, a LAN system in which personal computers can share a printer has been described, but the present invention can be similarly applied to a printer sharing system for information processing equipment other than personal computers, such as a word processor.

[Effects of the Invention] As detailed above, according to the present invention, while applying a method for connecting information processing equipment such as a personal computer to a LAN, the printer connection program originally included in the information processing equipment can be changed. Printers within a LAN system can be shared without any hassle.

[Brief explanation of drawings]

Figure 1a is a block diagram showing the overall configuration of a LAN (local area network) system according to an embodiment of the present invention, and Figure 1b is shown in Figure 1a.
2 and 3 are block diagrams showing conventional examples of the LAN adapter. 31a to 31d...Personal computer (PC), 32a, 32b...LAN adapter, 33...
Printer, 34...Printer server, 51a-51
d...Series input/output controller (SIO, communication interface), 52a to 52d, 62a to 62d...
Printer interface, 53... LAN controller, 61a to 61d... serial interface (communication interface).

Claims (1)

[Claims] 1 A second communication interface compatible with the first communication interface of the information processing equipment and a local area network controller for controlling data transmission and reception between the local area network and the information processing equipment, A local area network adapter connected to the workpiece is provided with a second printer interface compatible with the first printer interface of the processing equipment, and print data generated by the processing equipment is transmitted through the first printer interface. The local area network system is characterized in that the information is received by the second printer interface and transmitted by the local area network controller to a printer server connected to the local area network.