JPH0410749A - Modem - Google Patents

Abstract

PURPOSE:To make it possible to sufficiently separate a network control unit(NCU) from a MODEM circuit inspite of a compact MODEM unit and to reduce load required for developing the MODEMS of many standards by constituting the MODEM unit of the 1st board for mounting common circuit elements and the 2nd board for mounting elements whose functions are different in each standard and arranging the modular jack and a bus connector on the peripheral end part of the 1st board. CONSTITUTION:The MODEM unit is provided with the 1st metallic circuit board 10 provided with the modular jack 20 and the bus connector 22 on respectively opposed peripheral end part and mounting other circuits and the 2nd metallic circuit board 12 mounting circuit elements different in each MODEM standard, provided with leads 16 on its peripheral end parts and having a mounting area smaller than that of the 1st base 10. The 1st and 2nd circuit boards 10, 12 are arranged in parallel through a resin-made casing 14 and electrically mutually connected through the leads 16 of the 2nd circuit board 12. Consequently, the preparation of specific sheilding structure can be made unnecessary, the NCU can be sufficiently separated from the MODEM circuit and load for development can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a modem, and more particularly to a network control device and an intelligent modem incorporating a modem control device.

(D) Conventional technology In order to perform data communication between data terminal devices, the communication speed, data bit length, and parity of each communication device are required.
It is necessary to match the presence/absence and type of bits, transmission code, synchronization method, communication method, transmission control procedure, etc. Therefore, in order to reduce the burden on the data terminal device, a modem has been proposed that incorporates software for data communication and a dedicated microcomputer. Such modems are called intelligent modems because they can automatically make various connections necessary for data communication by simply inputting simple commands from a data terminal device.

In addition, voice band modems (hereinafter simply referred to as modems) that use the public telephone line as a transmission path must have functions that do not interfere with the public telephone line itself or other users. There is a demand for a function that allows highly reliable data communication even when the signal is weak.

For these reasons, today's modems are often designed with large-scale circuits, and today's common modems have the circuit configuration shown in FIG.

Referring to FIG. 4, such a modem has a microcomputer (60) that interprets commands input from a data terminal device (not shown) and performs a predetermined operation, and a microcomputer (60) that connects this microcomputer (6o) and the data terminal device. 1” ROM (64), 1200b supplies program data such as communication protocols to the connected DTE interface (62) and microcomputer (60), or control data for setting various modes of the modem.
ps PSK/FSK modulation/demodulation circuit (68), 300bp
s FSK modulation/demodulation circuit (70), transmission amplifier (72),
Receiving amplifier (74), tζth push button for automatic transmission.
a modem section comprising a tone/pulse dialer (76) for generating dial signals and dial pulse signals;
A line transformer (78), a line filter (80), a dial relay (82), and a line filter (80) connect this modem section and the telephone line network (12) under predetermined electrical conditions.
) (hereinafter referred to as the NCU unit).

The DTE interface (62) stores the parallel data of a data terminal equipment (hereinafter referred to as DTE) such as a personal computer (not shown) in its internal register, and then transfers the data to the microcomputer (62).
60) and conversely to the micro combi coater (60).
), and various PIO and USART are used. DTE for modem
5TC9610 (Seiko Epson Corporation) is known as the interface (62).

The microcomputer coater (60) interprets the meaning of the command manually input from the DTE and causes each function inside the modem to perform a specific operation6.When it detects the start code of the command, it detects the end code of the command. The data that is manually input is stored in a built-in memory called a command buffer until the command is detected, and when the command is completed, the command decoding unit checks the validity of the contents of this buffer and sequentially converts it into specific internal commands. Perform the processing to do. For example, the microcomputer for this modem is 5TC962.
0 (Seiko Epson Corporation), etc. are known. but,
With slight design changes, it is possible to use a general-purpose microcomputer.

The transmitting amplifier (72) is connected to the tone/pulse dialer (76).
) or the modulated output of either the PSK/FSK modulation/demodulation circuit (68) or the FSK modulation/demodulation circuit (7o) is output to the NCU section, and the reception amplifier (74)
The output of the CU section is sent to the PSK/FSK modulation/demodulation circuit (6
8), output to either the FSK modulation/demodulation circuit (70).

The operation of the modem configured as described above is as follows.

To start data communication, the microcomputer (
60) based on the address signal specified by the ROM (
64) is supplied to the microcomputer (60), and the communication standard (BELL/
CCITT standard), communication speed (30C)/1200bp
s) It is checked whether various modes such as data format matching and depth switch mode switching match.

If the various modes match, D on the responding side (not shown)
TE's modem phone number is entered manually by appropriate means,
The telephone number is manually entered into the DTE interface (62). It is also transferred to the microcomputer (60) to decode the telephone number. The results decoded by the microcomputer (60) are sent to the tone/pulse dialer (76). Therefore, if the public telephone line is a push-button dial line, a 1-tone signal is output from the tone/pulse dialer (76) and passed through the transmitting amplifier (72) and line transformer (78) Transferred to line (11, 12).

When the responding modem automatically receives the call in response to this tone signal, the responding modem sends an answer tone for the connection procedure to the calling modem.

The calling modem detects whether the answer tone is a predetermined answer tone for the calling modem;
If it is a predetermined answer tone, the communication state is entered.

When the communication state is established, the parallel data of the DTE on the calling side is input to the DTE interface (62), and the data is further transferred to the microcomputer (60). Next, at least when the parallel data is output from the microcomputer (60), it is converted into serial data and sent to the FSK modulation/demodulation circuit (70). Here the digital signal is converted to an analog signal,
The frequency is modulated based on the communication standard, and the transmission amplifier (7
2) is sent to the responding modem via the line transformer (78).

On the other hand, the frequency-modulated analog signal from the DTE on the responding side is sent to the modem on the calling side.
8), FSX modulation/demodulation circuit (
70). Here, the analog signal is converted into a digital signal and sent to the calling DTE via the DTE interface (62). As a result, the calling party's D
Half-duplex communication is achieved between the TE and the responding DTE.

(c) Problems to be solved by the invention The standards for network control devices and intelligent modems with built-in modem control devices include the type of public telephone network, communication speed, data pit length, presence and type of parity bits, The number of transmission codes determined by combinations of transmission codes, synchronization methods, communication methods, transmission control procedures, etc. is extremely large.

Therefore, in consideration of modem development efficiency, modem versatility, and practicality, efforts have traditionally been focused on developing modems that can comply with a wider range of standards.

However, for example, modems that use multi-function integrated circuits that can be used for both PSK and FSK modulation circuits, or modems that have dialers that can support both push-button dial lines and rotary dial lines, are suitable for specific applications. Not only does this result in excessive quality, but it also has the drawback of not being able to meet the demand for miniaturization of modems.

Furthermore, since there are standards that cannot be met even with such a modem, there is also the drawback that it is difficult to create a series of modems based on standards within an appropriate range.

Therefore, the first object of the present invention is to provide a modem that can meet the demands of any modem standard with appropriate performance, and also to provide a compact modem that can easily be made into a series of modem standards. It is about providing.

Furthermore, a modem formed on a large board has a problem in that it cannot be inserted into a DTE slot like a ROM card due to the strength of the board.

Therefore, the second object of the present invention is to
The objective is to provide a simple and compact modem that can be inserted and installed in a DTE slot.

Additionally, in general terms, although it is known that the use of hybrid ICs can reduce the size of circuit devices,
As mentioned above, it is difficult to implement each of the modems, which have a large number of standards, as a hybrid IC from the viewpoint of development costs.

Therefore, a third object of the present invention is to provide a modem that is easy to develop even when the modem standard is made into a series. In other words, the object is to provide a modem structure that can be made into a high-print IC.

Furthermore, conventional modems are mounted on resin printed circuit boards, and modems built into data terminal equipment require a special shielding structure, or Care had to be taken to place the circuit elements and modem.

Therefore, a fourth object of the present invention is to provide a modem that does not require a special shield structure and can be placed at any position in a data terminal device.

Matoko, network control unit (NCU) frame
The ground must be wired separately from the modem's signal ground, and must be connected to the data terminal housing at the shortest possible distance.For modems with a built-in network control unit (NCU), the ground must be connected to the frame ground. The connection was complicated.

In particular, it is difficult to connect the Freno ground of modems used in laptop-type data terminal equipment.

Therefore, a fifth object of the present invention is to provide a modem in which the frame ground can be easily connected.

(d) Additional means to solve the problem The above problem can be solved by providing the module jack and bus connector at opposite peripheral ends, line transformer, ROM,
A metal first circuit board on which common functional circuit elements compatible with a relatively wide range of other modem standards are mounted; a second circuit board made of metal and having a smaller mounting area than the first circuit board; the first and second circuit boards are arranged in parallel via a resin casing; The invention is solved by the modem of the present invention, characterized in that the first and second metal circuit boards are electrically connected by the leads of the metal circuit board.

(E) The modem of the present invention, which uses two metal circuit boards, the first and second, as working circuit boards, has a reduced planar area and eliminates the need for a special shield structure. Furthermore, a simple grounding means via a metal circuit board can be used for the frame ground of the network control unit (NCU).

In addition, the high-strength metal circuit board has a modular junk and a pass connector on opposing peripheral edges, making it simple and compact, allowing it to be inserted into a DTE slot and used.

Furthermore, the arrangement of modular jacks and path connectors on opposite peripheral edges of the first circuit board also facilitates separation of the network control unit (NCU) and modem circuitry even when the modem is configured in a compact size. can be done satisfactorily.

Furthermore, the modem has a first circuit board that mounts common functional circuit elements that can be compatible with a relatively wide range of standards, and a first circuit board that mounts different circuit elements for each standard, and has a smaller mounting area than the first circuit board. Since it is divided into a second circuit board that is formed in The problem is significantly reduced, making it easier to create a series of modem standards.

(f) Embodiment An embodiment of the present invention will be described with reference to FIGS. 1 to 3. Note that FIG. 1 is a plan view of the embodiment, and FIG. 2 is a side view thereof, partially shown in cross section.

As shown in FIGS. 1 and 2, the modem of the present invention includes a metal circuit board (3) which is a hybrid IC with functions commonly compatible with modems of a wide range of target standards. 10) and functions that differ depending on the standard or only functions that correspond to a relatively small number of standards are implemented as a hybrid IC. It has a fixed structure via.

The modem of the present invention, which is designed to be usable by being inserted into a slot of a DTE, includes the first circuit board (10).
DT modular jack (20) for connecting the modem of the invention to the public telephone line and a DT at opposite peripheral ends of the DT
E is equipped with a path connector (22) for connecting to the inside of the DTE, and when installed in the DTE, the modular seat
0) is arranged near the opening surface of the DTE.

In order to separate the modem circuit from the network control unit (NCU), which is a problem in modems with high-density mounting of circuit elements, a modular jack (20) is installed at the opposite peripheral edge of the first circuit board (10). and a path connector (22), and a line transformer (24) is arranged adjacent to the modular jack (20) at the arrangement line of the modular jack (20) and the path connector (22), Further path connector (22)
A second circuit board (12) is arranged adjacent to the second circuit board (12).

The first and second circuit boards (1, 0) (12) are formed by forming a wiring pattern on a metal board via an insulating resin layer, and in a particularly preferred embodiment in which aluminum is used, an anode After forming an oxide film on the surface by oxidation treatment, a wiring pattern is formed via an insulating resin layer. These first and second circuit boards (10)
(12) and the resin casing (14) are usually fixed using an adhesive sheet called J-sheet (trade name).

In the area surrounded by the casing (14) on the first circuit board (]0), functions that can commonly support modems of a wide range of standards are implemented as a hybrid IC, and the components and circuits are They are formed on a circuit board 10) and interconnected by wiring patterns. Further, functions that differ depending on the modem standard or only functions corresponding to a relatively small number of standards are mounted on the second circuit board (12) as high-print ICs. This second circuit board (1
2) is designed and developed for each modem standard, but its mounting area is smaller than that of the first circuit board (]0), so the burden of development is significantly reduced.

In the illustrated embodiment, these first and second circuit boards (
10) The electrical connection of (12) is on the second circuit board (]2)
The plurality of REITs (16) provided in the circuit board (]0
) The pad (18) formed on the pad (18) is soldered to the pad (18) by other means, but any connection means such as a socket may be used.

The embodiment will be further described with reference to the circuit diagram in FIG.

The modem of the present invention includes a microcomputer (30) that decodes commands manually input from a DTE (not shown), a ROM (26) that supplies control data such as transmission control procedures and communication methods to the microcomputer (30), and a microcomputer (30) that supplies control data such as transmission control procedures and communication methods to the microcomputer (30). A DTE interface (32) that connects the coater (30) and the internal path of the DTE according to a predetermined procedure;
Deep switch (34) that sets the mode of the TE interface (32), first and second modulation/demodulation circuits (36") (38), dialer (40), receiving amplifier (42), transmitting amplifier (44) ) and line transformer (
24) etc.

There is no need to change the function for each modem standard, or a microcomputer (30
), DTE interface (32), receiving amplifier (4
2) and the transmitting amplifier (44) are mounted in chip form on the above-mentioned] circuit board (10) at a position below the second circuit board (12), that is, at a position surrounded by the casing (14). be done.

In conventional modems, multi-function integrated circuits are typically used for the reasons mentioned above, but in the modem of the present invention, single-function integrated circuits are used as the first and second modem circuits (36) (38). Integrated circuits with a limited range of functions or functions are selectively used. For the same reason, a dialer (40) that is compatible with either a push-button dial line or a rotary dial line is selectively used.

However, only a single function or limited functions are mentioned here.
The range of functions is expressed relative to all target modem standards; for example, it is possible to use a dialer that is compatible with both push-button dial lines and rotary dial lines. The first one is a functional circuit that differs depending on the Kowara modem standard, or a functional circuit that corresponds to a relatively small number of standards.
and second modulation/demodulation circuit (36) (38) dialer (4)
0) is mounted in the form of a chip on the second circuit board (12).

The dashed-dotted lines in the figure indicate the first and second circuit boards (10) (
12). That is, the microcomputer (30) DT inside the area surrounded by the dotted chain line.
Circuit elements such as the E interface (32), the receiving amplifier (42), and the transmitting amplifier (44) are mounted on the first circuit board (
10), and the first and second modulation/demodulation circuits (36
) (38) and the dialer (40) are mounted on the second circuit board (12).

The ROM (26) is preferably implemented using a socket if a change in user specifications is expected, and more preferably an EPROM. However, since the structure and implementation method of ROM (26) are outside the scope of the present invention, it will simply be expressed as ROM (26).At this point, it is no longer possible to change the data in ROM (26). However, the arrangement of the ROM (26) is not limited to the illustrated position.

The common connection end of the capacitor C constituting the line filter (50) is connected to the first circuit board (10), and a locking mechanism of the first circuit board (10), such as a screw or click stop mechanism, is connected to the first circuit board (10). is used to connect to the DTE housing.

(1) Effects of the Invention As described above, according to the present invention, (1) Since the modem is constituted by two circuit boards on which circuit elements are mounted in the form of chips, it is possible to facilitate a modem that occupies a small planar area. be able to.

(2) A metal circuit board is used, and at least one side of the modem structure is completely shielded with metal, so the internal elements of the data terminal equipment and the modem are connected only or without consideration to the orientation of the shielding surface. Mutual interference can be prevented. Therefore, when designing a mobile terminal device, it is possible to provide a modem that is easy to layout and install.

(3) A first circuit board that mounts circuit elements that are commonly used in modems of a wide range of standards, and a second circuit board that mounts circuit elements that have different functions depending on the standard and that has a smaller mounting area than the first circuit board. Since the modem is constructed from a circuit board, the burden of developing modems of multiple standards is reduced.

(4) If a metal circuit board is used, securely ground the frame ground of the network control unit (NCU section) by fixing the modem to the data terminal device, or by other simple means. be able to.

(5) Reliability is improved because the chip-shaped circuit element is arranged in the sealed space formed by the first circuit board, the second circuit board, and the casing.

(6) modular at opposite peripheral edges of the first circuit board;
Jacks and bus connectors are arranged respectively, a line transformer is arranged on the arrangement line adjacent to the modular jack, and a second circuit board is arranged adjacent to the bus connector. However, the network control device and modem circuit can be sufficiently separated.

[Brief explanation of drawings]

FIG. 1 is a plan view of an embodiment of the present invention, FIG. 2 is a side view showing a part of the embodiment in cross section, and FIG. 3 is a circuit diagram of the embodiment.
FIG. 4 is a circuit diagram of a conventional modem. 10 first circuit board, 12 second circuit board,
14・Casing, 16 Lead, 18 Pad, 20 Modular seat, 22 Bus connector, 24 Line transformer, 26・ROM.

Claims (5)

[Claims] (1) A metal first circuit with modular jacks and bus connectors at opposite peripheral ends and implementing line transformers, ROMs, and other common functional circuitry compatible with a relatively wide range of modem standards. A second circuit board made of metal, on which different circuit elements are mounted for each modem standard, has leads at the peripheral edge, and has a smaller mounting area than the first circuit board. The first and second circuit boards are arranged in parallel via a resin casing, and the first and second metal circuit boards are electrically connected by the leads of the second metal circuit board. A modem featuring: (2) Common function circuit elements of the first circuit board and circuit elements of the second circuit board are arranged in a sealed space formed by the first and second circuit boards and the casing, and the modular jack, line transformer 2. A modem as claimed in claim 1, characterized in that irregular parts, such as bus connectors, etc., are arranged on the other plane of the first circuit board. (3) Modular jack and bus on the first circuit board
2. The modem of claim 1, wherein a line transformer is disposed between the connectors and adjacent to the modular jack, and a second circuit board is disposed adjacent to the bus connector. (4) The modem according to claim 1, wherein a DTE interface, a microcomputer, a transmission amplifier, and a reception amplifier are mounted on the first circuit board, and a modulation/demodulation circuit and a dialer are mounted on the second circuit board. 5. The modem of claim 1, wherein the signal ground of the modem is connected to the bus connector and the frame ground of the network controller is connected to the first metal circuit board.