JPH0628285A - Data communication system - Google Patents

Abstract

PURPOSE: To reduce external interface hardware to improve the flexibility by providing hardware peculiar to a specified data communication medium in different housings. CONSTITUTION: An external interface adapter is installed in an independent housing which is restricted by smallness of an external interface card 210. A host bus interface logic 215 and an interrupt logic 220 are provided to control the communication with a host computer through interfaces 222 and 224. Interfaces 222 and 224 are directly connected to a host data bus 225 of the host computer. The host bus interface 215 is executed for the modem card 210 by the host computer. In this case, a request to transmit or receive information to the host computer is processed.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to computer systems and computing devices. In particular, the present invention relates to computer systems and computing devices that are connected to external devices.

[0002]

BACKGROUND OF THE INVENTION In the computer industry, an important feature of computer systems is their ability to connect to external devices and communicate over standard communication media. This capability provides a means for a computer located at one location to communicate with a computer located at another location. Other characteristics of this communication have spawned the computer network, computer bulletin board, and online database industries. In one form of data communication, a computer transfers information to another computer over a telephone line. In other computer network applications, computers transfer information through dedicated communication lines that use established network protocols. In each of these data communication applications, a particular hardware element (ie, an external interface device or circuit card) requires a computer to access and transfer information using a particular communication medium. is necessary. One such external interface element of a computer system capable of communicating over a telephone line is a modem. A modem or modulator / demodulator system provides a means of converting an almost digital signal on a computer into an analog signal compatible with standard telephone communication lines. Thus, prior art modems are typically a means of coupling the modem to the computer system on the one hand and the modem to the telephone network on the other hand. A modem includes hardware that converts a computer digital signal into a communication medium analog signal and vice versa. The modem device must also include the hardware that electrically isolates the modem and computer from the telephone network. Isolation hardware is necessary to prevent transient voltage surges from affecting the telephone line or the computer system. It is typically the telephone company that manages the telephone network that needs this separate hardware.

[0003]

Although the physical size of prior art modems is becoming smaller, this reduction in physical size is limited by the size of the signal conversion and separation hardware. ing. Some of the components of this prior art conversion isolation hardware (i.e., transformer) cannot be reduced in size below certain limits without losing the functional properties required for the device. Therefore, the physical size of prior art modems is limited to no less than the minimum size possible for the translation isolation hardware required.

Translation isolation hardware is also typically present in prior art computer networks that utilize direct connect networks. A twisted pair Ethernet network is one such example. However, again, the size of the translation isolation hardware limits the size of the external interfaces needed to communicate over these networks.

In addition to the problem of reducing the size of the external interface hardware of the prior art, the prior art attempts to maintain compatibility with a particular external interface configuration when utilizing more than one communication medium. Another problem arises. For example, a modem designed to operate in accordance with standards established for the United States telephone network may not work properly with foreign telephone systems operating under different conformance standards.
This problem is especially troublesome when the number of foreign countries is large and telephone network standards are diverse. Prior art modems targeted to each of these telephone networks must be modified to accommodate these foreign telephone systems. This telephone network suitability issue, together with the fact that the modem needs to be adapted to a particular computer system, poses a significant configuration management issue for modem manufacturing.

Similarly, numerous computer networks have been established that operate under various hardware interface standards. When used with a variety of different data communication media, in order to reduce the size of external interface hardware and increase flexibility,
There is a need for better ways to connect external devices to computers.

[0007]

SUMMARY OF THE INVENTION The present invention is an improved external interface arrangement in which the hardware specific to a particular data communication medium is provided in a separate housing. There is provided an external interface adapter, referred to herein as an external interface card, that is separate from another housing that contains other external interface hardware. With this method, the hardware installed in the external interface card can be used for various different communication media. In addition, the external interface card can be reduced to a size that is impossible with the conventional technology.

In a first embodiment, a computer has a thin modem housing (ie, an external interface card) that can be directly connected to the computer's data bus using the bus connector on the modem housing.
Is coupled to the telephone network using a modem circuit installed inside. Modem circuits in the external interface card include host bus interface and interrupt logic components, clock circuits and power management circuits,
And a modem chip setting logic component. The thin modem housing also includes a seven pin adapter connector that couples the modem circuit to a telephone adapter circuit that is installed in another housing (ie, the external interface adapter) and connected to a short cable.

The telephone adapter circuit of the first embodiment is installed in a housing separate from the thin modem housing (ie, the external interface adapter). The telephone adapter circuit of the present invention comprises signal converting means, telephone network separating means, and telephone network logic means. The signal converting means converts the analog control signal into a digital control signal. Telephone network isolation means prevent transient power surges from affecting the computer or telephone network. Telephone adapter logic means provides the means for interpreting various signals for a particular telephone network. The telephone adapter of the present invention also has two external interfaces. The first external interface is particularly adapted to the adapter connector of the modem housing. The second external interface of the telephone adapter is configured to couple the adapter to an outlet that fits a particular telephone network. Telephone adapters are designed with all the circuitry that is specific to a particular telephone network. Thus, the modem circuit can be used with a variety of different telephone network protocols without the need for modification. In addition, large and bulky electronic components can be moved out of the modem housing, which can reduce the size of the modem housing. These and other advantages of the invention will be apparent upon reading the following detailed description of the preferred embodiments.

In a second embodiment, the computer is coupled to a data communication network (eg, twisted pair Ethernet network) using an external interface card and a separately housed external interface adapter. The external interface card comprises circuitry for interpreting and processing network control protocols and data. The external interface adapter is
It includes circuitry that converts signals and electrically isolates the computer from the network.

[0011]

DETAILED DESCRIPTION OF THE INVENTION An improved means and method for coupling a computer or computing device to a data communications medium using external interface circuitry and external interface adapters contained in separate housings is described. The techniques of the present invention can be applied to computer systems, instrumentation systems, peripherals, printers, or any other electronic device that needs to communicate with other devices. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. In other instances, well-known structures and circuits have not been shown in detail in order not to unnecessarily obscure the present invention.

Referring to FIG. 1, external interface card 110 and external interface adapter 12
A physical configuration of 0 is shown. As shown, the external interface card housing 110 and the external interface adapter 120 are used for
5 is a physically separated housing connected at 5.

In the first embodiment, the external interface card 210 is a thin card of a 2400 bit per second modem plugged into a computer data bus. The card 210 is a busbar connector 11 of the card 210.
2 is used to connect to the data bus. External interface card 210 is designed for use with laptops and / or notebook personal computers because of its compactness, light weight, and low power consumption. The external interface card 210 is particularly suitable for this purpose because of its small physical size. In the first embodiment, the external interface card 210
Has a length of 85.6 mm (± 0.2 mm) and a width of 54.0 mm (±
0.1 mm) and thickness 3.3 to 5.0 mm (± 0.1
mm) in a rectangular housing. The physical dimensions of the card comply with the guidelines set forth by the Japan Electric Industry Development Association (JEIDA).

The external interface adapter 320 is
The external interface card 210 is installed in another housing that is not restricted by the small size of the external interface card 210. In the first embodiment, the external interface card 2
The circuitry contained in 10 and the external interface adapter 320 consists of state-of-the-art circuitry configured to allow the computer to communicate with other devices over standard telephone lines. The circuits contained in the external interface card 210 and the external interface adapter 320 of the first embodiment will be described in the next chapter, but are shown in FIGS.

Referring to FIG. 2, there is shown a block diagram of circuitry associated with the first embodiment external interface card 210 (ie, a modem card). Figure 2
2, the modem card 210 is shown as composed of host bus interface logic 215, interrupt logic 220, clock circuitry 230, emulation logic 240, power management logic 250, and modem chipset logic 260. Host bus interface logic 215 and interrupt logic 220 are provided to control communication with the host computer by interfaces 222 and 224. Interfaces 222 and 224 are designed to be directly coupled to host data bus 225 of the host computer. Bus connector 112 of external interface card 110
Are provided for this purpose as shown in FIG. The host bus interface logic 215 is implemented by the host computer on the modem card 210. It is configured to process requests to the host computer to send or receive information. The interrupt logic 220 sends data or control information to the UART bus 235.
Provides a means to interrupt the host computer when available from. The configuration of host bus interface logic 215 and interrupt logic 220 are well known to those skilled in the art. The main goal of the host bus interface logic 215 is to decode the card select signal sent from the host computer to the modem card 210.

Bus interface logic 215 and interrupt logic 220 are connected to modem card 210 via bus 235.
To communicate with other circuits in. The emulation logic 240 and the power management logic 250, as shown in FIG.
Connected to 5. The emulation logic 240 is
It provides a means to emulate control signals for a modem card 210 that is not directly supplied by the host computer. The power management logic 250 uses the modem card 21
0 controls the power supplied to the circuit. Power management logic 2
50 has a mode in which the modem card 210 enters a low power state while inactive. Modem card 210
Remains in this low power mode until it receives a request from the host computer or receives a ringing signal from the telephone line. The modem card 210 has a clock circuit 230.
It also has The clock circuit 230 includes a crystal that synchronizes the internal operation of the modem card 210 and the data transfer. The circuits contained in emulation logic 240, power management logic 250, and clock circuit 230 are well known to those skilled in the art.

Both emulation logic 240 and power management logic 250 are coupled to a serial bus 245. Bus 245 is a serial data bus which provides a data communication path for modem chipset logic 260. The modem chipset logic 260 is a component well known to those of ordinary skill in the art. One such configuration of modem chipset logic 260 is a highly integrated, low power, high performance, information processing modem chipset manufactured by Intel Corporation of Santa Clara, Calif. Under the product name 89C024LT. . This modem chipset is. It has two chip modem logic configurations consisting of an analog front end (ie, chip # 89027) and a microcontroller (ie, chip # 89C026LT). The microcontroller performs all digital signal processing for processing modem signals, as well as performing modem control functions. The analog front end components perform 2-wire and 4-wire telephone line connections, digital-to-analog and analog-to-digital conversion, and data filtering functions. The modem chipset logic 260 is directly connected to the adapter connector 211, which has at least six external pins that couple the modem card 210 to the external interface adapter 320. The adapter connector 211 is a modem card 210
The height of the adapter connector 211 can be less than the thickness of the modem card 210 (that is, 3.3 to 5.0 mm) or less.

Referring now to FIG. 3, external interface adapter 320 is shown in association with external interface card connector 211 and communication medium 340. As mentioned above, the adapter connector 211 is
It is physically mounted on the edge of the external interface card 210. The external interface adapter 320 is a hardware coupling means, typically a conductive cable 315.
(Ie, the cable 115 shown in FIG. 1) is coupled to the external interface 211. Referring again to FIG. 3, the external interface adapter 320 includes a data communication medium 340 by the hardware coupling unit 330.
Is bound to. Typically, the hardware coupling means 330 is a conductive cable connecting the external interface adapter 320 to the data communication medium. In the first embodiment, the data communication medium 340 uses an outlet having an RJ-11 type receptacle to couple the means 3 together.
A telephone network coupled to 30. The telephone network can use two or four wire communication media. In the second embodiment, the data communication medium 640.
Is a twisted pair ethernet cable having a coupling means compatible with the hardware coupling means 630. The external interface adapter 320 and the coupling means 315 and 330 form a state path between the external interface card 210 and the data communication medium 340.

Referring now to FIG. 4, there is shown an electrical schematic diagram of the circuitry contained within the first embodiment external interface adapter 320. As mentioned above, the external interface adapter 320 of the first embodiment is configured to convert and electrically isolate telephone network interface signals. FIG. 4 shows a circuit that performs this function. Referring now to FIG. 4, the external interface adapter 320 comprises an external interface connector 410 for coupling the external interface adapter 320 to the external interface coupling means 115. The adapter connector 410 has one pin for the pin output of the six signals used by the external interface card 210 and the common location signal 417. As shown in FIG. 4, the external interface adapter 320
Are shown to consist of a transformer means 420, a signal conversion means 430, an electrical isolation means 440, and an external interface 450 for connecting to a data communication medium 340. In the first embodiment, the external interface 450
Couples the external interface adapter 320 to the telephone network. In this configuration, only two signal lines 453 and 452 are needed to couple to the telephone network. In a four-wire telephone network, four signal lines are provided. The current of these signals is
Limited by 1 and 462. Electrical protection means 440 is also provided to block incoming signals when the power surge produces signals that reach dangerous high voltage levels. First
In one embodiment, the electrical protection means 440 is a metal oxide varistor that provides the electrical surge protection needed to prevent damage to the external interface 320. The use of metal oxide varistors for this purpose is a well known technique known to those skilled in the art. Resistor 426, capacitor 427,
And diodes 428 and 429 are also provided in the circuit shown in FIG. These components 426-429 are
It is another means of electrically isolating the circuitry within the external interface adapter 320 from the telephone network. The signal line 453 continues past the resistor 461 and is directly connected to the transformer 420. The signal line 452 continues beyond the resistor 462 to the signal conversion means 430. The signal conversion means 430 comprises a chip commonly available in the electrical industry. One such chip is Theta, Wakefield, Massachusetts.
-J. Inc. Is manufactured under the part name TS120. This device provides the means for converting or decoding the incoming telephone line to generate two main signals. The first signal is an off-hook control on signal line 432 that simulates the situation when the telephone handset is lifted from the switch hook to activate the telephone line and dial. The second main signal supplied from the signal converting means 430 is supplied via the signal line 433. The off-hook signal is provided at pin 413 to adapter connector 410. The ring detect signal is provided at pin 415 to the adapter connector 410. The response to the off-hook is provided at pin 416 to adapter connector 410. The reply to the ring detect signal is provided by pin 414 to adapter connector 410. In addition to the off-hook and ring detect signals, the modulated data is on pin 4
11 and 412 supply the adapter connector 410. This modulated data is electrically isolated from the telephone network by using the transformer 420. In the first embodiment, the transformer 420 is a standard one-to-one transformer commonly known and available in the industry. This transformer 420 serves to electrically isolate the telephone network from the external interface card 210 and the host computer to which it is connected.

Referring now to the second embodiment as illustrated in FIG. 5, the external interface card 510
A thin twisted pair Ethernet network interface card that plugs into a computer data bus. Twisted Pair Ethernet Interface Card 510
Is a fully twisted wire pair Ethernet 802.3 10
It includes circuitry designed to be an interface compatible with the BASE-T computer network interface. The card 510 connects to the data busbar using the busbar connector 112 of the card 510.
In the second embodiment, the external interface card 510
(Ie twisted pair Ethernet network card)
Has a length of 85.6 mm (± 0.2 mm) and a width of 54.0 mm (±
0.1 mm) and thickness 3.3 to 5.0 mm (± 0.1
mm) in a rectangular housing. The physical size of the card conforms to the guidelines set forth by the Japan Electric Industry Development Association (JEIDA).

The external interface adapter 620 according to the second embodiment also includes the external interface card 510.
It is installed in a separate housing that is not restricted by the small size of. . In a second embodiment, the circuits contained within the external interface circuit 510 and the external interface adapter 620 are twisted circuits designed to allow a computer to communicate with other devices over a twisted pair Ethernet network. It consists of a line-to-ethernet interface circuit. . Second
The circuitry contained within the external interface card 510 and external interface adapter 620 of this embodiment is described below and illustrated in FIGS.

Referring to FIG. 5, there is shown a block diagram of the circuitry associated with the second embodiment external interface card 510 (ie, twisted pair Ethernet network card). Referring to FIG. 5, twisted pair Ethernet network card 510 includes host bus control and timing logic 515, host bus transceiver means 5
20, host bus interface logic 540, LAN
Controller logic 530, EPROM 550, SRAM 55
1 and an analog unit 560 are shown. Control and timing logic 515 and transceiver means 520 are provided to perform host address decoding, signal buffering, and loopback control. Control and timing logic 515, in the second embodiment, is implemented as a single erasable / programmable logic unit (EPLD), commonly available under the part name 5C090 from Intel Corporation of Santa Clara, Calif. The transceiver means 520 is commonly available from Toshiba Japan under the part name 74ACT2458.
It is a bus transceiver. Both control and timing logic means 515 and transceiver means 520 are circuits well known to those skilled in the art. Host interface logic 54
0 consists of an arbiter, a 2-channel 10 MHz DMA controller, and an interrupt unit, and controls the flow of information between the host computer and the network card 510. Host interface logic 540 is part number 8 from Intel Corp. of Santa Clara, Calif.
A commercially available chip sold as 2560. Control and timing logic 515, transceiver 520, and host interface logic 540 communicate with the host computer via bus interfaces 522, 424, and 526. Interfaces 552, 524, and 526 are designed to be directly coupled to the host data bus 225 of the host computer. External interface card 510
Edge connector 112 is provided for this purpose.
The edge connector 112 is shown in FIG.

Referring again to FIG. 5, EPROM 550.
Is a read-only storage means containing network node address information, configuration data, and a diagnostic code for the network card 510. EPROM 550, which is commonly available from Toshiba of Japan, has an access time of 120
27C256-as 32K x 8-bit EPROM of ns
It is a well-known chip available with a part number of 120v10. The SRAM 551 is used as a data buffer for both transmission and reception network data. S
The RAM can be implemented as an 8K × 8 bit static storage means with an access time of 100ns. Such storage means is available from Toshiba of Japan under the part number TC556.
Commonly available under 5 AFL. LAN controller logic 530 handles information processing between the host and the twisted pair Ethernet interface. The LAN controller 530 performs functions including Manchester encoding / decoding and information collision detection. LAN controller 530 is also commonly available as part number 82590 from Intel Corporation of Santa Clara, Calif. Resources of the network card 510 that can access the host computer (ie, host interface logic 540, EPROM
550, SRAM 551, and LAN controller 530)
Are mapped into the storage address space of the host computer. In addition, each of these resources is a network card 51.
It is coupled to the local bus 545 inside the 0. The transceiver means 520 also includes a local bus 54 as shown in FIG.
Connected to 5. Local bus 545 provides a path for control and data communication between components within network card 510. The analog unit 560 performs analog-to-digital and digital-to-analog conversion between the network card 510 and the external interface adapter 620. Analog unit 560
Connects to the host computer via the LAN controller logic 530 via the data path 561. The analog unit 560 is also coupled to the adapter connector 511. The following four signals are supplied to the adapter connector 511. TDO- (transmitted data), TDO + (differential response to TDO-), RDI- (received data), RDI +
(Differential reply to RDI-). These signals are therefore
For the second embodiment, the external interface adapter 620 can be accessed.

Referring now to FIG. 6, external interface adapter 620 is shown in association with external interface card connector 511 and communication medium 640. As described above, the adapter connector 511 is physically installed on the edge of the external interface card 510. The external interface adapter 620 is a hardware coupling means, typically a conductive cable 61.
5, coupled to the external interface 511.
A similar cable 115 is shown in FIG. Referring again to FIG. 6, the external interface adapter 620 is coupled to the data communication medium 640 by hardware coupling means. Typically, hardware coupling means 630
Is a conductive cable that connects the external interface adapter 620 with a data communication medium. In the second embodiment, the data communication medium 640 is the hardware coupling means 6
It is a twisted pair Ethernet network with coupling means fitted at the ends of 30. The external interface adapter 620 and the coupling means 615 and 630 form a path between the external interface card 510 and the twisted pair Ethernet data communication medium 640.

Referring now to FIG. 7, there is shown an electrical schematic diagram of the circuitry contained in the second embodiment external interface adapter 620. As mentioned above, the second embodiment external interface adapter 620 is designed to condition and electrically isolate signals for the twisted pair Ethernet network interface. . FIG. 7 thus shows a circuit which performs this function. Referring now to FIG. 7, the external interface adapter 620 includes an external interface connector 710 that couples the external interface adapter 620 to the external interface coupling means 615. The adapter connector 710 is an external interface card 510.
Pin out up to nine signals (or power and ground) used by the. Two pins, 711 and 71
8 is provided for a common ground signal. One open pin 719 is provided for shielding the connector. Pin 71
5 and 712 are external interface cards 510
Used by the external interface adapter 620
Illuminates the LED to indicate that the Ethernet network is functioning properly.

In the second embodiment, the external interface card 510 includes the remaining four of the nine data lines,
TDO- (transmitted data), TDO + (differential response to TDO-), RDI- (received data), RDI + (RD
Differential response to I-). As shown in FIG. 7, the external interface adapter 620 is shown to be composed of two major components, a filter pack 740 and a choke inductor set (common node choke) 750. Choke inductor set 750 is coupled to four signal lines (761, 762, 763, and 766) that are coupled to adapter connector 760. Adapter connector 760 interfaces with the twisted pair Ethernet network.
The choke inductor set 750 is provided to block or limit the common node signal from the scattered differential data signals on lines 761, 762, 763, and 766. Therefore, the choke inductor set 750 acts as a noise filter for the circuits in the external interface adapter 620. Since the choke inductor set 750 is composed of a set of inductors, the device is limited to a size below the minimum inductor size. In the present invention, the physical size of choke inductor set 750, however, does not affect the physical size of external interface card 510. This is because the inductor set 750 is not housed in the external interface card 510. This is an important advantage over the construction of the present invention. The choke inductor set 750 is a component well known to those skilled in the art.
Such a device is commonly available from Valor of San Diego, Calif. Under the part number PT3868. The choke inductor set 750 further includes capacitors (737, 738) and resistors (734, 73).
5 and 736). Capacitor 73
7 and 738 provide direct current (DC) isolation for the circuit. Resistors 734, 735, and 736 provide a means of adjusting the operation of the circuit by appropriately adjusting the resistance level of the resistors. In some embodiments, resistor 736 may be omitted altogether. Choke inductor set 7
50 is a capacitor (737, 73) as shown in FIG.
8) and resistors (734, 735, and 736) to filter pack 740. Filter pack 740 is a commonly available electrical component that filters and electrically isolates the signals on lines 747, 748, 749, and 770. The filter pack 740 is
Used to filter out high frequency noise and eliminate radio frequency emission problems. In addition to filtering, filter pack 7
40 includes transformer means within the device. This transformer means provides electrical isolation of the circuit between the external interface card 510 and the twisted pair Ethernet network 640. As with the inductors in the choke inductor set 750, the transformer means in the filter pack 740 is limited to a size that is smaller than appropriate for the required operating characteristics of the transformer. This size can be larger than is possible to accommodate the housing of the external interface card 510. However, the filter pack 740 is not compatible with the external interface adapter 6
Since it is stored in 20, the physical size of the filter pack 740 does not matter. Filter pack 740
Is commonly available from Valor, San Diego, Calif., Under the part number PT3877. The filter pack 740 further includes connector pins 717, 71.
6, 714, and 713 are coupled to the adapter connector. The signals on these pins are sent to or received from the external interface card 510. Pins 742 and 745 of filter pack 740 are grounded through capacitors 732 and 733.

[0027]

As noted above, improved means and methods have been disclosed for coupling a computer or computing device to a data communication medium using external interface circuitry and external interface adapter circuitry contained in separate housings. .

Although the present invention has been shown in relation to particular embodiments, it should not be considered so limited. Instead, the invention is limited only by the claims.

[Brief description of drawings]

FIG. 1 illustrates the physical configuration of the preferred embodiment, showing an external interface card coupled to an external interface adapter with a short cable.

FIG. 2 is a block diagram of a circuit included in the external interface card according to the first embodiment.

FIG. 3 is a block diagram showing the telephone interface adapter of the first embodiment in relation to an external interface.

FIG. 4 is an electrical schematic diagram of the circuitry contained in the telephone interface adapter of the first embodiment.

FIG. 5 is a block diagram of a circuit included in the external interface card of the second embodiment.

FIG. 6 is a block diagram of a second embodiment of a twisted pair Ethernet interface adapter in association with its external interface.

FIG. 7 is an electrical schematic diagram of the circuit contained in the twisted pair Ethernet interface adapter of the second embodiment.

[Explanation of reference numerals] 110,210 External interface card 120,320 External interface adapter 112 Bus connector 215 Host bus interface logic 220 Interrupt logic

Claims (1)

[Claims] 1. A data communication system comprising a communication medium having a data bus and a computing device, wherein information on the data bus is transferred to another device by the communication medium, the transfer information being coupled to the data bus. An external interface card for processing the card, the card including a bus connector for connecting the card to the data bus, and an adapter connector for connecting the card to an external interface adapter, and An external interface adapter for converting a signal generated by an external interface into a form compatible with the communication medium, the adapter being coupled to the adapter interface of the external interface card and also connected to the communication medium. , The external in Separately from receiving the over face card, data communication system, characterized in that it comprises an external interface adapter includes means for electrically isolating from said communication medium to the external interface card.