JP3362547B2 - Communication adapter - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an external communication apparatus such as a facsimile apparatus connected via a communication line, and
Regarding a communication adapter connected to a host device having an initiator function of performing polling via a bus such as an SI bus, particularly when the host device polls the communication adapter, a communication phase between the communication adapter and an external communication device is set. The present invention relates to a communication adapter that accurately notifies a host device and takes consistency with the host device. 2. Description of the Related Art Conventionally, there has been known a communication system in which a communication adapter such as a facsimile adapter is connected to a SCSI bus of a host device and bidirectional communication between the host device and the communication adapter is performed. As a result, communication between the host device and the communication device is realized via the communication adapter. Here, SCSI (Small Computer System)
m Interface is ANSI (American National Sta
ndard Institute). According to the SCSI standard, command / data transfer is performed between an initiator that issues an instruction and a target that receives and executes the instruction. Therefore, both the host device and the communication adapter in the conventional communication system have realized the two-way communication by having both the function of the initiator and the function of the target. However, many personal computers or workstations used as host devices usually have only the function of an initiator. Therefore, when the host device having only the function of the initiator and the communication adapter having only the function of the target are connected by the SCSI bus, communication (transmission) from the target to the initiator cannot be performed. As a result, it has been difficult for the communication adapter to notify the host device that it has data received from an external communication device connected via a communication line. In order to solve this problem, Japanese Patent Laid-Open Publication No.
Japanese Patent No. 36928 discloses that a host device as an initiator determines whether or not there is data received from the outside via a communication line to a communication adapter as a target.
A data communication device that realizes bidirectional communication between a host device and a communication adapter by periodically confirming, that is, polling using a CSI command is described. In this data communication device, not only the received data but also a communication phase between the communication adapter and the external communication device is notified (see a communication phase CP in FIG. 3 (d) described later). Here, the communication phase is a rule on a communication protocol for managing a communication state. For example, when the communication adapter is a facsimile adapter and the external communication device is a facsimile device, a communication phase (communication phase A) of facsimile communication between the facsimile adapter and the facsimile device as shown in FIG. To E), the communication state is managed. In FIG. 7, a phase A is a sequence of call setting and line establishment. Phase B is a pre-processing step of facsimile message transmission, and is a sequence for confirming the state of terminals and transmission paths and controlling the terminals. Here, confirmation of the transmission / reception preparation state and the synchronization state of the terminal is performed. Phase C is a phase for performing facsimile message transmission and controlling during message transmission.
Message transmission and its confirmation and synchronization maintenance are performed. Phase D is a process of performing message termination and acknowledgment, and in the case of performing continuous transmission, returning to phase B or phase C and repeating transmission. Phase E
Is the process of call recovery, ie, line disconnection. Therefore,
In the case of facsimile communication, communication phase A → B →
Through C → D → E, communication is managed and executed. However, in the above conventional data communication apparatus, the communication phase B ends in a very short time and shifts to the next communication phase C. Depending on the interval or timing of polling of the communication adapter (facsimile adapter) from the host, a state occurs in which the host device cannot confirm the communication phase B. As a result, the communication between the host device and the communication adapter may become inconsistent, and a malfunction or a system down may occur. Therefore, the present invention eliminates such a problem and accurately confirms the communication phase between a communication adapter and an external communication device, thereby ensuring consistency between the host device and the communication adapter. It is another object of the present invention to provide a communication adapter capable of preventing malfunction and system down. According to the present invention, there is provided a communication adapter as a target which is connected to a host device as an initiator via a bus and is connected to an external communication device via a communication line. Management means for managing and storing a communication phase between the communication device and the communication adapter; and determining whether or not there is a communication phase that has not been notified to the host device based on the management content of the management means. Determining means, and notifying means for notifying the host device of the unreported communication phase in response to a polling request from the host device when the determining means determines that there is a communication phase not notified. And According to the present invention, the management means manages and stores the communication phase between the communication adapter and an external communication device connected to the communication adapter via the communication line. Then, the determining means determines whether or not the communication phase not notified to the host device is stored in the managing means. The notifying means notifies the communication phase in response to the polling request from the host device each time. However, if the determining means determines that there is a communication phase not notified, the notifying means does not notify the polling request from the host device. For example, the oldest communication phase stored in the storage means is notified. Thus, it is possible to maintain communication consistency between the host device and the communication adapter. Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration of a communication system including a facsimile adapter according to one embodiment of the present invention. In FIG. 1, the communication system includes a facsimile adapter 10, a facsimile adapter and a SCSI.
It comprises a host device 20 connected via a bus B, and a facsimile device 30 connected via a communication line L to a facsimile adapter 10. The facsimile adapter 10 has a function of a target for the host device 20 as an initiator, and controls the whole of the facsimile adapter 10.
11, a communication control unit 12 connected to the communication line L for controlling communication with the facsimile machine 30, a communication phase storage unit for sequentially storing communication phases in the communication control unit 12, and deleting the communication phase notified to the host device 13. a communication phase determining unit 14 for determining whether or not any of the communication phases stored in the communication phase storage unit 13 has not been notified to the host device 20; It has a SCSI control unit 15 that performs communication control with the host device 20 including control for notifying the polling request in order from the oldest communication phase. The communication control unit 12, the communication phase storage unit 13,
The communication phase determination unit 14 and the SCSI control unit 15 are connected to the CPU via the internal bus B1,
Under the control of U11. The host device 20 periodically polls the facsimile adapter 10 via the SCSI bus, and when the facsimile adapter 10 receives data from the facsimile device 30, acquires the received data. Further, the host device 20 has an initiator function for the facsimile adapter 10 and can perform facsimile transmission to the facsimile device 30 via the facsimile adapter 10. In the communication between the facsimile adapter 10 and the facsimile apparatus 30, normal facsimile communication is performed under the management of the communication phase of the facsimile communication shown in FIG. Next, a communication procedure between the host device 20 and the facsimile adapter 10 will be described. FIG. 2 is a diagram showing a schematic sequence between the host device 20 and the facsimile adapter 10. In FIG. 2, the host device 20 inquires of the facsimile adapter 10 whether there is reception from the facsimile device 30 by periodic polling (S20).
1). Here, the communication control unit 12 is connected to the facsimile machine 30.
Receives the incoming facsimile via the communication line L, the SCSI controller 15 notifies the host device 20 that the reception has occurred (S2). The host device 20, which has received the notification of the occurrence of the reception, issues a SCSI LUN (Logical Unit Number) allocation request to the facsimile adapter 10. In contrast, facsimile adapter 1
0 assigns the communication line L and the LUN that have received the call in association with each other, and then notifies the host device 20 of the assigned LUN (S3). This LUN is identification information for mutually recognizing the facsimile communication received by the facsimile adapter 10 between the host device 20 and the facsimile adapter 10. Therefore, in the subsequent sequence, the set LUN is used each time until the communication between the host device 20 and the facsimile adapter 10 is completed. On the other hand, the host device 20, which has received the set LUN from the facsimile adapter 10, issues a facsimile reception to the facsimile adapter 10 notifying that facsimile reception is possible (S4). Thereafter, the host device 20 uses the SCSI command “SEND MESSAGE” to the facsimile adapter 10 to
A FAX status request is made periodically (S5). The facsimile adapter 10 having received the FAX status request performs a communication phase history management process and a communication phase inquiry / notification process which will be described later.
A communication phase is set, and the SCSI command “GET” is sent to the host device 20 including the set communication phase.
FAX status using "MESSAGE" (S
6). Thereafter, the above-described sequence of S5 and S6 is repeated as many times as necessary by polling of the host device 20. After the facsimile reception of the facsimile adapter 10 ends (communication phase E of facsimile communication), the facsimile adapter 10
The FAX status (S8) including the communication phase E is notified to the FAX status request (S7). The host device 20, which has received the FAX status S8,
The release of the currently allocated LUN is notified (S
9) The communication of the currently set LUN between the host device 20 and the facsimile adapter 10 ends. Here, the detailed configuration of the FAX status request and the FAX status will be described with reference to FIG. As described above, the FAX status request and the FAX status use the SCSI standard. FIGS. 3A and 3B are diagrams showing a command format and a data format of a FAX status request. FIG. 3A shows the format of the SCSI command "SEND MESSAGE (6)".
The LUN 30 set by the facsimile adapter 10 is written in this command. FIG.
(B) shows “SEND MESSAGE DAT” which is SCSI data.
A "format, and data to be notified to the facsimile adapter 10 is transmitted. FIGS. 3C and 3D are diagrams showing a command format and a data format of the facsimile status. Figure (c) shows the SCSI command "G
ET MESSAGE (6) "format and fax
As with the status request command, the set LUN
31 is written. FIG. 4D shows the format of “GET MESSAGE DATA” which is SCSI data. In this data, a communication phase CP between the facsimile device 30 and the facsimile adapter 10 is written, and the host device At the same time, the status and the result of facsimile communication are stored between 5 bytes and 187 bytes and transmitted to the host device 20. Next, the history management processing of the communication phase and the inquiry / notification processing of the communication phase in the facsimile adapter 10 will be sequentially described with reference to FIGS. As shown in FIG. 4, in the history management processing procedure of the communication phase, first, when the communication control unit 12 receives an incoming call from the facsimile machine 30 via the communication line L,
The CPU 11 initializes the communication phase storage unit 13 (Step 101). Thereafter, communication control is performed by the communication control unit 12 in accordance with the facsimile communication protocol (step 102). This communication procedure is monitored and the CPU
11 determines whether the communication phase has changed (step 103). If the communication phase does not change, the determination in step 103 is repeated. If the communication phase changes, a new communication phase is additionally stored in the communication phase storage unit 13 (step 104), and the process proceeds to step 103. As described above, the communication phase storage unit 13
Each time a change occurs in the communication phase, a new communication phase is sequentially stored, and the history of the communication phase is managed. Next, as shown in FIG. 5, in the inquiry / notification process of the communication phase, first, the SCSI control unit 15
It is determined whether a FAX status request has been received from the host device 20 via the CSI bus B (step 20).
1) Repeat the determination in step 201 until a FAX status request is received. SCSI controller 15 is fax
Upon receiving the status request, the communication phase determining unit 14
First determines whether a communication phase is stored in the communication phase storage unit 13 (step 202). As a result, when a communication phase is stored in the communication phase storage unit 13, the communication phase determination unit 14 notifies the SCSI control unit 15 of the oldest communication phase stored in the communication phase storage unit 13 (step 203). ), Delete the oldest communication phase stored in the communication phase storage unit 13 (step 204), and proceed to step 206. On the other hand, in step 202, the communication phase storage unit 1
When the communication phase is not stored in the communication control unit 3, the communication phase determination unit 14 notifies the SCSI control unit 15 of the current communication phase in the communication control unit 12 (step 20).
5) Go to step 206. In step 206, the SCSI control unit 15 notifies the host device 20 of the notified communication phase as a part of the SCSI data shown in FIG. 3D, and proceeds to step 201 to execute the above-described processing in the communication phase E. Repeat until. That is, if there is any omission in communication phase notification, the communication phase is stored in the communication phase storage unit 13, the oldest communication phase among the stored communication phases is notified to the host device 20, and the communication phase If there is no notification omission, the communication phase is not stored in the communication phase storage unit 13, and the current communication phase is notified to the host device 20. Therefore, the host device 2
0 indicates the facsimile adapter 10 and the facsimile machine 3
The communication phase between 0 can be accurately recognized. As a result, consistency between the host device 20 and the facsimile adapter 10 is obtained, and the host device 2
0 malfunction or system down can be prevented beforehand. Further, a detailed configuration of the communication phase storage unit 13 will be described with reference to FIG. Here, the communication phase storage unit 13 performs storage management employing the ring buffer method, and the communication phase is registered each time the communication phase changes, and when the notification to the host device 20 is completed, the registered communication phase is registered. The communication phase is deleted. In FIG. 6, the communication phase storage unit 13 has a read pointer indicating a position where the communication phase is read and a write pointer indicating a position where the communication phase is written. The write pointer and the read pointer are located at the head address at the time of initialization, and when the communication phase is registered, the value of the write pointer is set to “1”.
When the notification of the communication phase is completed, the read pointer deletes the read communication phase and adds "1" to the value of the read pointer. Therefore, when there is no delay in the notification of the communication phase, the positions indicated by the write pointer and the read pointer are the same, and the communication phase is not registered at the position indicated by the write pointer and the read pointer, and the current communication is not performed. The phase will be notified. The storage contents in FIG. 6 indicate that the current communication phase is the communication phase D, and the communication phase B and the communication phase C are not notified. After reaching the final address, the write pointer and the read pointer return to the head address and repeat the same processing. As described above in detail, according to the present invention, the communication between the host device and the communication adapter is made consistent, and the malfunction of the host device and the communication adapter or the system down can be prevented. It has the advantage that it can be prevented. [0039]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a configuration of a communication system including a facsimile adapter according to one embodiment of the present invention. FIG. 2 is a diagram showing a schematic sequence between the host device 20 and the facsimile adapter 10; FIG. 3 is a diagram showing a detailed configuration of a FAX status request and a FAX status. FIG. 4 is a flowchart showing a history management processing procedure of a communication phase in the facsimile adapter 10; FIG. 5 is a flowchart showing a communication phase inquiry / notification processing procedure in the facsimile adapter 10; FIG. 6 is a diagram showing a detailed configuration of a communication phase storage unit 13; FIG. 7 is a diagram showing an outline of a communication phase of facsimile communication. [Description of Signs] 10 facsimile adapter 20 host device 30 facsimile device 11 CPU 12 communication control unit 13 communication phase storage unit 14 communication phase determination unit 15 SCSI control unit L communication line B SCSI bus B1: Internal bus

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04N 1/32-1/34 H04N 1/00-1/00 108

Claims (1)

Claims: 1. A communication adapter as a target connected to a host device as an initiator via a bus and connected to an external communication device via a communication line. Management means for managing and storing a communication phase between the device and the communication adapter; and determining means for determining whether or not there is a communication phase that has not been notified to the host device based on the management content of the management means. And a notifying unit for notifying the host device of the unnotified communication phase in response to the polling request of the host device when the determining unit determines that there is a communication phase of which the notification has not been performed. Communication adapter.