JPH09204372A - Serial interface - Google Patents

Abstract

PROBLEM TO BE SOLVED: To confirm the operation of a serial interface by the inspection of one time using one kind of a loop-back jig. SOLUTION: In this serial interface 16 for connecting equipments, since an input port for the inspection (input port by TEST1 and TEST2) for turning an input port number same as an output port number is provided, all loop pairs are secured relating to the input ports and output ports and the operation of all the ports is confirmed by the inspection of one time by one kind of the loop-back jig 19.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a serial interface for connecting an external device such as a personal computer to a device such as a facsimile machine.

[0002]

2. Description of the Related Art Conventionally, a facsimile machine has been used as a stand-alone machine, but recently, attention has been paid to its printer function, and for example, a form of use in which a personal computer is connected to be used as a printer for the personal computer is also available. Has appeared (for example, Japanese Patent Laid-Open No. 6-2
25072). In this case, the facsimile apparatus is equipped with a serial interface such as RS232C to enable connection of a personal computer.

FIG. 3 shows an example of a part of the configuration of a conventional serial interface 21 provided in an interface control unit of a facsimile machine. Although this serial interface 21 has a 10-pin structure, the input control signal S
3 input pins for D, RTS, DTR, 5 output pins for output control signals RD, CTS, DSR, DCD, CI
It is set in the book. An input buffer (receiver) 22 is provided on the input pin line to form an input port, and an output buffer (driver) is provided on the output pin line.
23 is provided to form an output port.

Consider the operation confirmation in the process inspection of the serial interface 21. There are two conventional inspection methods for confirming this operation. The first method is an operation inspection method performed by actually connecting a personal computer to the serial interface 21. The second method is an inspection method using a loopback jig.

[0005]

However, in the case of the working method, it is necessary to actually connect the personal computer and operate the personal computer, which is troublesome and time consuming.

On the other hand, the inspection method using the loopback jig is a simple method in that it can be inspected without a personal computer, but in reality, the inspection is performed using two types of loopback jigs. I have to do it twice, and it takes a lot of time and labor for inspection. That is, in the case of the serial interface 21 shown in FIG. 3, the input pin for the input control signal SD and the output pin for the output control signal RD are connected,
Input pin for input control signal RTS and output control signal CTS
A first loopback jig configured to connect an output pin for input control signal DTR and an input pin for input control signal DTR and an output pin for output control signal DSR; and, for example, an input pin for input control signal SR Two types of jigs, a second loopback jig configured to connect the output control signal DCD output pin and the input control signal RTS input pin and the output control signal CI output pin, are provided. It is necessary to prepare and carry out in two steps.

Therefore, an object of the present invention is to provide a serial interface capable of confirming the operation by a single inspection using one type of loopback jig.

[0008]

According to the present invention, a serial interface for connecting devices is provided with as many test input ports as the number of input ports is equal to the number of output ports. Therefore, it is possible to secure all the loop pairs for the input port and the output port, and it is possible to confirm the operation of all the ports with one inspection using one type of loopback jig.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to FIGS. First, the serial interface of this embodiment is applied to a facsimile apparatus as one of the embodiments. The hardware configuration of the facsimile apparatus 1 will be described with reference to FIG. A CPU 2 that controls each unit is provided. This CPU2 has
ROM 3 that stores fixed data including basic programs and inspection programs, RAM that stores various data as needed
4. Data storage memory for storing image data (SA
F) 5 is connected via a bus line 6. Further, a scanner 7 that performs a basic document reading operation as the facsimile device 1 and a printer 8 that prints out received image data and the like are provided, and are provided to the CPU 2 via the control units 9 and 10 and the bus line 6, respectively. It is connected.
Further, a coding / decoding unit (DCR) 11 that performs a predetermined coding or decoding process on image data, and a modulation / demodulation circuit (modem) 12 that modulates a transmission signal and demodulates a reception signal.
Is also connected to the CPU 2 via the bus line 6. The modem 12 is connected to a public telephone line via a network control unit (NCU) 13.

Further, as an external device using the printer 8 as a printer, for example, an interface (I / I) for connecting a personal computer (PC) 14
F) A control unit 15 is provided. This I / F control unit 1
5 is provided with a serial interface (serial I / F) 16 for actually connecting the cable & connector pulled out from the PC 14 side.

As this serial I / F 16, for example, RS232C is used. FIG. 1 shows an example of a part of the configuration of the serial I / F 16 according to the present embodiment. Although this serial I / F 16 has a 10-pin structure, it has three input pins for input control signals SD, RTS, and DTR, and output control signals RD, CTS, DSR, and DC.
Five output pins for D and CI are set. Further, two input pins for the test input signals TEST1 and TEST2 are set. An input buffer (receiver) 17 is provided on the input pin line to form an input port, and an output buffer (driver) 18 is provided on the output pin line to form an output port. That is, in the present embodiment, in comparison with FIG.
By adding two input ports by the input pins for the test input signals TEST1 and TEST2, the number of input ports becomes 5, and the ports are configured so as to be the same as the number of output ports.

According to this structure, the serial I / F
Since the number of input ports and the number of output ports in 16 are the same, the inspection for confirming the operation of the serial I / F 16 can be performed by one inspection using one type of loopback jig. That is, as shown in FIG. 1, the input pin for the input control signal SD and the output pin for the output control signal RD are connected, the input pin for the input control signal RTS and the output pin for the output control signal CTS are connected, and the input control is performed. Signal D
The input pin for TR and the output pin for the output control signal DSR are connected, the input pin for the test input signal TEST1 and the output pin for the output control signal DCD are connected, and the test input signal TE is connected.
All of the input / output loop pairs can be formed by using only one type of loopback jig 19 configured to connect the input pin for ST2 and the output pin for output control signal CI. It is possible to check the transmission and reception confirmation of. Therefore, the inspection process can be simplified and can be completed reliably and in a short time.

In the present embodiment, the present invention is applied to a serial interface provided in a facsimile machine for connecting a personal computer, but the present invention is not limited to such an example, and a serial interface in which the number of input ports is smaller than the number of output ports is used. The same applies to the case of an interface.

[0014]

According to the present invention, in the serial interface for connecting the devices, the test input ports are provided so as to make the number of input ports the same as the number of output ports. All loop pairs can be secured, so that the operation of all I / O ports can be confirmed by one-time inspection using one type of loopback jig, and the inspection process can be simplified and completed in a reliable and short time. be able to.

[Brief description of drawings]

FIG. 1 is a schematic circuit diagram showing a part of a serial I / F extracted including a connection of a loopback jig as an embodiment of the present invention.

FIG. 2 is a block diagram showing a hardware configuration of a facsimile device.

FIG. 3 is a schematic circuit diagram showing a part of a serial I / F of a conventional example extracted.

[Explanation of symbols]

 1,14 Equipment 16 Serial interface

Claims (1)

[Claims] 1. A serial interface for connecting devices, wherein the serial interface is provided with as many test input ports as the number of input ports is equal to the number of output ports.