JPH09146720A - Adaptor for connecting printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily set up a communication mode by switching a printer identification (ID) signal for identifying a two-way/ one-way communication mode by hardwawre. SOLUTION: An adaptor using IEEE P1284 standard for a communication system with a printer is provided with a switching control circuit 9 for switching a printer ID signal, i.e., select-in signal 101, for identifying the two-way/one-way communication mode of the printer and an auto-field signal 102 by the communication mode and a mode changing switch 10. When the switch 10 is turned off (when the two-way mode is selected), a select-in signal 101a and an auto-field signal 102a are sent to the printer as they are, and when the switch 10 us ON (when the one-way mode is selected), the signal 101a is turned off and the signal 102a is turned off in the OFF state of the signal 101a. When signal 101a is turned on, the signal 102a is sent to the printer as it is.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer connection adapter, and more particularly to a printer connection functioning as a network print server adapter for connecting a bus LAN and a printer so that the printer can be shared on a network. Regarding the adapter.

[0002]

2. Description of the Related Art Conventionally, this type of printer connection adapter (hereinafter simply referred to as an adapter) has a structure shown in FIG. FIG. 3 is a block diagram showing a configuration of a conventional example. L
A communication control circuit 31 that controls communication with the AN side, a memory 34 that stores data and control programs, a data processing circuit 32 that edits and processes data, a printer interface circuit 33 that controls data input / output with a printer, and these It comprises a CUP 35 and the like that controls each part according to the sequence of the program.

Regarding the communication system between the adapter and the printer, the conventional unidirectional communication mode, which is based on Centronics, is replaced with the bidirectional communication mode IEEE P1284.
Many are adopting a compliant interface, which is currently the standard. The reason is that the utility software for more effective use of the print server adapter is provided exclusively by each company because of the ease of network operation management, and the adapter needs to receive various status information from the printer. Because of that.

Among these adapters having a bidirectional communication mode, there are some adapters which can also select a unidirectional / bidirectional communication mode in accordance with the printer selection from the utility software. The means for controlling has two communication modes of unidirectional / bidirectional in the printer interface circuit 33.
This is realized by switching the control program stored in the memory 34 as indicated by.

The structure can be classified into a built-in type formed as an option board inside the printer and an external type formed as a board unit independently of the printer. The built-in type is designed under the usage conditions only for the built-in printer device, but the adapter main body is basically the same as the circuit configuration shown in FIG.

The IEEE used by many adapters
A description will be added to the bidirectional communication mode of the EP1284. The communication mode is an extension of the conventional Centronics standard, and uses conventional signals for bidirectional communication.
The adapter first generates an identification signal that is a combination of certain special signals called negotiation operation in order to check whether the printer is a compliant device (device capable of bidirectional communication). From the response (combined state of certain signals) obtained, it is determined whether the printer is bidirectional. If the response is other than the response that bidirectional communication is possible, the printer automatically determines that unidirectional communication is possible and performs the next communication. This is the printer interface automatic discrimination method in the adapter.

[0007]

As described above, since the conventional adapter performs the bidirectional / unidirectional switching of the communication mode by software, a host computer connected to the LAN or a designated terminal issues this switching instruction. It is necessary to carry out with a predetermined program from the device. Therefore, when the hardware or software on the instruction side is changed, it is necessary to set this switching every time, and there is a problem that setting takes time.

[0008]

The printer connection adapter of the present invention is a printer connection adapter comprising communication connection means for the LAN side, data processing means for editing and processing data, and interface means for the printer side. The interface means is provided with a switching means capable of switching the identification signal for identifying the communication mode to be sent to the printer to either the bidirectional communication mode or the unidirectional communication mode on the hardware and sending the identification signal.

For example, the interface means uses an IEEE P1284 standard two-way communication mode as a communication method with the printer, a select-in signal and an auto field signal are used as the identification signals, and the switching means is the printer. When in the bidirectional communication mode, the identification signal is sent as it is, and when the printer is in the unidirectional communication mode, the select-in signal is always switched to the off state and is sent, and the auto-field signal is turned on by the select-in signal. When it is off, it is sent as it is, and when it is off, it is always switched to the off state to be sent respectively.

Further, the structure is an external structure independent of the printer to be connected.

[0011]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an embodiment. A communication control circuit 1 that controls communication with the LAN side, a memory 4 that stores data and control programs, a data processing circuit 2 that edits and processes data, a printer interface circuit 3 that controls data input / output with a printer, and these. It is composed of a CPU 5 which controls each part according to a sequence of programs, a switching control circuit 9 which switches an identification signal for identifying a printer, a mode switching switch 10 and the like.

The LAN is connected by a connector 6, and the printer is connected by a printer connection port 8. The printer interface circuit 3 outputs a signal group capable of realizing a bidirectional communication mode as a communication mode with the printer to the input / output connector 7, and their interface standard is IEEE.
Based on the P1284 standard. Input / output connector 7
Among the signals output to the printer, the select-in signal 101a and the auto feed signal 102 are used as printer identification signals.
Although there is a, these are once output to the printer connection port 8 via the switching control circuit 9.

Next, the operation of each part of the present invention will be described with reference to FIG. FIG. 2 is a timing chart for explaining the operation of the printer identification signal. When the adapter is powered on and started to operate, first, the printer interface circuit 3 executes a negotiation operation to check whether the printer is a compliant device (having bidirectional parallel) defined by IEEE P1284. Specifically, the printer identification signal, that is, the select-in signal 10
Turn off 1a and turn on auto feed signal 102a
This operation is started by setting.

As shown in FIG. 2A, when the mode selector switch 10 is OFF (bidirectional mode selected), the switching control circuit 9 outputs two signals as they are to the printer connection port 8 as they are. Therefore, the negotiation operation executed by the adapter is transmitted to the printer as it is, and if the printer is a compliant device, a corresponding response is made.

Further, as shown in FIG. 2 (b), when the mode changeover switch is ON (unidirectional mode selection), the changeover control circuit 9 receives the select-in signal 101a and the auto feed signal 102a, respectively. 101
b, signal conversion is performed in the form shown in the auto feed signal 102b. That is, the select-in signal 101a is OF
When F, the auto feed signal 102b is not output, and when the select-in signal 101a is ON, the audio feed signal 102b is output through. The select-in signal 101a itself is not output and the select signal 101b is OFF.
Becomes

Therefore, in this case, the negotiation operation is not transmitted to the printer, and the printer cannot respond to this operation. As a result, the adapter determines that the printer is not a compliant device, and processes the next communication mode as unidirectional. This is equivalent to the adapter being forcibly set to the unidirectional mode (the state transition to the compatibility mode referred to in IEEE P1284) regardless of the printer conditions.

[0017]

As described above, since the printer connection adapter of the present invention can easily switch the different printer identification signals in the bidirectional / unidirectional communication mode by the switch, the communication mode of the printer to be connected. The setting mode is fixed if this switch is switched according to the setting, and there is no need to redo this setting according to changes on the system side, as compared to the case of switching with software as in the past. is there.

Further, by making the structure an external type independent of the printer main body, it is possible to easily cope with a printer of bidirectional / unidirectional communication mode, and there is an effect that versatility is expanded.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an exemplary embodiment of the present invention.

FIG. 2 is a time chart showing the operation in FIG. 1 when (a) is a mode switch and when (b) is a mode switch.

FIG. 3 is a block diagram showing a configuration of a conventional adapter example.

[Explanation of symbols]

 1 Communication Control Circuit 2 Data Processing Circuit 3 Printer Interface Circuit 4 Memory 5 CPU 6 Connector 7 Input / Output Connector 8 Printer Connection Port 9 Printer Control Circuit 10 Mode Change Switch 101a Select-In Signal (Input) 101b Select-In Signal (Output) 102a Auto Feed signal (input) 102b Auto feed signal (output)

Claims (3)

[Claims] 1. A printer connection adapter comprising communication connection means for the LAN side, data processing means for editing and processing data, and interface means for the printer side, wherein the interface means sends a communication mode to the printer. An adapter for printer connection, comprising a switching means capable of switching an identification signal for identification to one of a bidirectional communication mode and a unidirectional communication mode on hardware and transmitting the identification signal. 2. The interface means uses an IEEE P1284 standard two-way communication mode as a communication method with the printer, a select-in signal and an auto field signal are used as the identification signals, and the switching means uses the printer. When in the bidirectional communication mode, the identification signal is sent as it is, and when the printer is in the unidirectional communication mode, the select-in signal is always switched to the off state and is sent, and the auto-field signal is turned on by the select-in signal. 2. When it is, it is sent as it is, and when it is off, it is always switched to the off state and sent respectively.
The printer connection adapter described. 3. The printer connection adapter according to claim 1, wherein the structure is an external structure independent of the printer to be connected.