JP2012114551A - Modulator-demodulator and communication device provided with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a configuration for control relative to an analog public switched telephone network and an IP network and also to reduce the load of a system control unit in a communication device having an analog facsimile communication function and a network facsimile communication function.SOLUTION: A fax modem 9 includes: a modulation and demodulation unit 92 for facsimile data; a VoIP data processing unit 93, a codec interface for fax 94 capable of connecting a codec for facsimile 10 for analog facsimile communication, and a codec interface for VoIP 95 capable of connecting a codec for VoIP 13. As the codec interfaces in the fax modem 9 control the codecs, a configuration for control relative to an analog public switched telephone network and an IP network becomes simple, and the load of a host CPU 6 can be reduced.

Description

  The present invention relates to a modem and a communication device including the same, and more particularly to a modem having a modem data modulation / demodulation function and a VoIP (Voice over Internet Protocol) data processing function, and a communication device including the modem. .

  A network facsimile machine having an analog facsimile communication function for connecting to an analog public network and performing facsimile communication using the analog public network and a network facsimile communication function for transmitting and receiving image information using the IP network. A device is known, and a device having an IP telephone call function has also been proposed (Patent Document 1).

  However, in the network facsimile apparatus described in Patent Document 1, the codec in the G3 facsimile modem is connected to the system control unit via the internal bus, and the system control unit controls the codec. There is a problem that the load is large.

  The public line network control device and the network transmission control unit are also connected to the system control unit via the internal bus, and the system control unit has a configuration for controlling them, that is, control over the public line network control and the IP network. There is a problem that the control is complicated because the parts for performing the above are distributed.

  The present invention has been made to solve such problems, and an object of the present invention is to control analog public line networks and IP networks in a communication apparatus having an analog facsimile communication function and a network facsimile communication function. It is to simplify the configuration for reducing the load on the system control unit.

The modem of the present invention is a modem having a modem for facsimile data, a processing unit for VoIP data, and a codec interface capable of connecting a codec for analog facsimile communication and a codec for VoIP.
The communication apparatus of the present invention is a communication apparatus having the modulation / demodulation apparatus of the present invention.

  According to the present invention, since the codec interface in the modem apparatus controls the codec, the configuration for controlling the analog public line network and the IP network of the communication apparatus by mounting the modem apparatus of the present invention on the communication apparatus. The load on the system control unit can be reduced.

It is a block diagram which shows the structure of the communication apparatus of the 1st Embodiment of this invention. FIG. 2 is a block diagram showing an internal configuration of a facsimile codec interface and a connection relationship with a facsimile codec in FIG. 1, and an internal configuration of a VoIP codec interface and a connection relationship with a VoIP codec. 2 is a diagram for explaining a data format conversion operation between data of a facsimile codec and data of a VoIP codec by the facsimile modem in FIG. 1. FIG. It is a flowchart which shows the procedure which performs telephone / facsimile automatic switching of a communicating party apparatus using the function of the facsimile modem of the communication apparatus of the 1st Embodiment of this invention. It is a block diagram which shows the structure of the communication apparatus of the 2nd Embodiment of this invention. FIG. 6 is a block diagram showing an internal configuration of a facsimile / VoIP codec interface in FIG. 5, a connection relationship with a facsimile codec, and a connection relationship with a VoIP codec. 6 is a flowchart showing master / slave switching operation of the facsimile modem of FIG. 5. It is a block diagram which shows the structure of the communication apparatus of the 3rd Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. In the following description, the facsimile is referred to as FAX and the interface is referred to as I / F.

[First Embodiment]
<Configuration of communication device>
FIG. 1 is a block diagram illustrating a configuration of a communication apparatus according to a first embodiment of this invention.
The communication apparatus includes a bus 1, an operation unit 2, a scanner 3, a printer 4, a LAN (Local Area Network) I / F 5, a host CPU (Central Processing Unit) 6, a ROM (Read Only) each connected to the bus 1. Memory) 7, RAM (Random Access Memory) 8, and FAX modem 9. The communication apparatus also includes a FAX codec 10, a DAA (Data Access Arrangement) 11, a VoIP codec 13, a telephone I / F (SLIC: Subscriber Line Interface Circuit) 14, and a telephone 15.

  The FAX modem 9 includes an H / S (handshake unit) 91, a modem unit 92, a VoIP data processing unit 93, a FAX codec I / F 94, a VoIP codec I / F 95, a DAA control I / F 96, and a telephone control I / F. F97 is provided.

  The H / S 91 is connected to the bus 1 and performs handshaking of data and commands between the host CPU 6 and the FAX modem 9.

  At the time of signal transmission, the modulation / demodulation unit 92 modulates FAX data (digital data encoded by MMR (Modified Modified READ) or the like) from the host CPU 6 into PCM (Pulse Code Modulation) data to generate a FAX codec I / F 94. When receiving a signal, the PCM data from the FAX codec I / F 94 is demodulated into FAX data and output to the host CPU 6.

  The VoIP data processing unit 93 has a codec format conversion function and a signal level conversion function. When sending a signal, the VoIP data processing unit 93 receives VoIP data (G.711 encoded data) from the host CPU 6 via the H / S 91 and uses it for VoIP. Codec 13 is G. If it corresponds to 711, the data is output to the VoIP codec I / F 95 as it is, and the VoIP codec 13 is set to G.711. If it is not 711 compatible, it is converted into PCM data and output to the VoIP codec I / F 95. At the time of signal reception, the VoIP codec 13 is set to G.264. 711, the data received from the VoIP codec I / F 95 is directly output to the host CPU 6 via the H / S 91. If not compatible with G.711, G. The data is converted into 711 encoded data and output to the host CPU 6 via the H / S 91. Further, the transmission / reception signal level is converted if necessary. In the following description, the VoIP codec 13 is G.264. 711.

  The FAX codec I / F 94 is a module having an SP (serial-parallel) conversion function and a PS (parallel-serial conversion) function for digital data handled by the FAX codec 10 and a timing adjustment function. The VoIP codec I / F 95 is a module having an SP conversion function, a PS conversion function, and a timing adjustment function for digital data handled by the VoIP codec 13.

  The DAA control I / F 96 is a module that controls the general public network (analog public line network) 12 connected to the DAA 11. The telephone control I / F 97 is a module for controlling the telephone I / F 14 and realizing a call using the telephone 15 connected to the telephone I / F 14.

  The FAX codec 10 is connected to the FAX codec I / F 94 and is a module that converts digital data handled by the FAX modem 9 and an analog signal for performing G3 FAX communication on the general public network 12. In general, a FAX codec handles PCM data and has a serial I / F whose codec is a master.

  The VoIP codec 13 is a module that is connected to the VoIP codec I / F 95 and converts digital data handled by the FAX modem 9 and an analog signal for the telephone 15. In general, the codec for VoIP is G. It has a serial I / F that handles 711 encoded data and the codec is a slave.

  The DAA 11 is a module that performs analog signal transmission to the general public network 12 and network I / F (2-wire to 4-wire conversion, hook control, call signal detection, etc.). The telephone I / F 14 is a module that controls the telephone 15 (power feeding, 2-wire to 4-wire conversion, ringing tone generation, hook detection, etc.).

  The communication apparatus having the above configuration can perform G3 FAX communication and VoIP call at the same time. First, signal processing of G3 FAX communication will be described. The FAX data sent from the host CPU 6 to the FAX modem 9 is modulated by the modulation / demodulation unit 92 to become PCM data, parallel-serial converted by the FAX codec I / F 94, and serially output to the FAX codec 10. The serial data is converted into an analog signal by the FAX codec 10, and the analog signal is converted from two to four lines by the DAA 11 and sent to the general public network 12. On the other hand, the analog signal received from the general public network 12 is converted into PCM data by the FAX codec 10 and then serially input to the FAX codec I / F 94 of the FAX modem 9. The serial input data is serial-parallel converted by the FAX codec I / F 94, and the parallel data is demodulated by the modem unit 92 and sent to the host CPU 6.

  Next, signal processing for a VoIP call will be described. The analog signal transmitted from the telephone 15 is converted from 2 to 4 lines by the telephone I / F 14 and then converted to G.264 by the VoIP codec 13. It is converted into 711 encoded data and serially input to the VoIP codec I / F 95 in the FAX modem 9. This serial input data is serial-parallel converted by the VoIP codec I / F 95. The parallel data is sent to the host CPU 6 after being subjected to the required digital signal processing by the VoIP data processing unit 93, and output from the LAN I / F 5 to the LAN. Is done. On the other hand, a VoIP packet input from the LAN to the LAN I / F 5 is sent from the host CPU 6 to the FAX modem 9. The FAX modem 9 receives the required digital signal processing by the VoIP data processing unit 93, performs parallel-serial conversion by the VoIP codec I / F 95, and serially outputs it to the VoIP codec 13. This serial output data is converted into an analog signal by the VoIP codec 13, and this analog signal is sent to the telephone 15 through the telephone I / F 14.

<Codec I / F for FAX, Codec I / F for VoIP>
Next, the FAX codec I / F 94 and the VoIP codec I / F 95 in FIG. 1 will be described in detail. FIG. 2 is a block diagram showing the internal configuration of the FAX codec I / F 94 in FIG. 1 and the connection relationship with the FAX codec 10, and the internal configuration of the VoIP codec I / F 95 and the connection relationship with the VoIP codec 13. is there.

  As shown in FIG. 2, the FAX codec I / F 94 includes an SP / PS conversion register 941, an internal timing generator 942, an SCK (serial synchronous clock) detector 943, buffers 944 to 947, and terminals T1 to T4. ing. Terminals T3 and T4 are bidirectional terminals capable of switching between input and output.

  As described above, a FAX codec generally has a serial I / F whose codec is a master (clock supply side). In FIG. 2, the FAX codec 10 becomes a master, generates a clock, and supplies it to the FAX codec I / F 94. The SP / PS conversion register 941 in the FAX codec I / F 94 becomes a slave (clock receiving side). The internal timing generator 942, the buffers 945 and 947, and the SCK detector 943 are set not to operate, and the terminals T3 and T4 are set to the input mode.

  There are SCK and FS (frame synchronization clock) as clocks. SCK and FS generated by the FAX codec 10 are input to the FAX modem 9 from terminals T3 and T4, respectively, and input to the SP / PS conversion register 941 through the buffers 944 and 946.

  The data includes SOD (serial output data) and SID (serial input data). The SOD is output from the SP / PS conversion register 941, transmitted from the terminal T1 to the outside of the FAX modem 9, and input to the FAX codec 10. The SID is output from the FAX codec 10, input to the FAX modem 9 from the terminal T 2, and sent to the SP / PS conversion register 941.

  The VoIP codec I / F 95 includes an SP / PS conversion register 951, an internal timing generator 952, an SCK detector 953, buffers 954 to 957, and terminals T5 to T8. Terminals T7 and T8 are bidirectional terminals capable of switching between input and output. The SCK detector 953 is set not to operate, and the terminals T7 and T8 are set to the output mode.

  As described above, a VoIP codec generally has a serial I / F whose codec is a slave. In FIG. 2, an internal timing generator 952 in the VoIP codec I / F 95 serves as a master, generates a clock, and supplies it to the VoIP codec 13.

  SCK and FS generated by the internal timing generator 952 are supplied to the VoIP codec 13 through the terminals T8 and T7 through the buffers 957 and 955, respectively, and SP / PS conversion through the buffers 954 and 956. It is supplied to the register 951. The SOD is output from the SP / PS conversion register 951, transmitted from the terminal T5 to the outside of the FAX modem 9, and input to the VoIP codec 13. The SID is output from the VoIP codec 13, input from the terminal T 6 to the FAX modem 9, and sent to the SP / PS conversion register 951.

  That is, the codec I / F 94 for FAX and the codec I / F 95 for VoIP are codecs having the same configuration that can be switched between master and slave, and are set in advance as slaves or masters depending on whether the connection partner is a master or a slave. The The state of the internal timing generator, the buffer, and the bidirectional terminal changes depending on whether it is set as a master or a slave. The SCK detection unit is used when automatically detecting whether the connection partner is a master or a slave based on whether or not SCK is input. This function will be described in the second embodiment.

<Data format conversion between FAX codec and VoIP codec>
The FAX modem 9 has a data format conversion function between the data of the FAX codec 10 and the data of the VoIP codec 13. By using this function, not only a VoIP call but also a call using the general public network 12 is possible without providing a switch.

  FIG. 3 is a diagram for explaining the data format conversion operation between the data of the FAX codec 10 and the data of the VoIP codec 13 by the FAX modem 9 in FIG. The VoIP data processing unit 93 includes a signal level conversion register 931. It also has a codec format conversion function and a signal level conversion function.

  As described above, the FAX codec 10 handles PCM data, and the VoIP codec 13 is G.264. 711 encoded data is handled. The codec format conversion function of the VoIP data processing unit 93 in the FAX modem 9 includes PCM data and G. This is a function for performing conversion between 711 encoded data. By using this function, the transmission signal is transmitted from the G.P. 711 encoded data is converted into PCM data and output to the FAX codec 10. For the received signal, the PCM data input from the FAX codec 10 is converted to G.711. The data is converted into 711 encoded data and output to the VoIP codec 13.

  The signal level conversion function is a function for improving the call quality by matching the signal level of the data of the VoIP codec 13 with the signal level of the general public network 12. That is, since there is an unloaded cable in the general public network 12, the attenuation of the signal level is larger than that of the VoIP call. Therefore, in order to correct it, the conversion value held in the signal level conversion register 931 is used to increase the level of the transmission signal than the signal of the VoIP call and decrease the level of the reception signal. Matched to the received signal level of VoIP call.

<TEL (telephone) / FAX automatic switching of the receiving device>
In the communication apparatus according to the present embodiment, a function that is enabled when the FAX modem 9 handles VoIP data includes a TEL / FAX automatic switching function of the receiving apparatus. This function will be described with reference to the flowchart of FIG. In this figure, the VoIP communication side is the communication apparatus of the present embodiment, and the reception FAX side is a reception side apparatus connected to the general public network via the IP network or gateway (not shown) of the LAN in FIG.

  First, a user's call operation to the telephone 15 on the VoIP communication side is notified to the host CPU 6 through the telephone I / F 14, the VoIP codec 13, the FAX modem 9, and the bus 1. Upon receiving this notification, the host CPU 6 generates a call signal and outputs it from the LAN I / F 5 to the LAN. This call signal is received on the reception FAX side (step S11). Since the TEL mode is set in advance on the reception FAX side, connection is made to the TEL side after an incoming call (step S12).

  Next, on the VoIP communication side, the transmission signal input from the telephone 15 passes through the telephone I / F 14 and is converted into VoIP data (G.711 encoded data) by the VoIP codec 13, and for VoIP in the FAX modem 9. Input from the codec I / F 95 to the VoIP data processing unit 93.

  The VoIP data input to the VoIP data processing unit 93 is subjected to CNG component cut processing here (step S2), sent to the host CPU 6, output from the LAN I / F 5 to the LAN, and transmitted to the reception FAX side.

  On the receiving FAX side, it is determined whether or not CNG is detected from the VoIP data (step S13). If not detected (step S13: No), the connection on the telephone side is continued (step S14) and detected. In this case (step S13: Yes), switching to the FAX side (step S15).

  In general, a communication device having a TEL / FAX automatic switching function (for example, a FAX telephone device) detects CNG sent from a transmission side device and switches from the TEL mode to the FAX mode. For this reason, if the CNG component is included in the call signal, there is a possibility that the mode is switched to the FAX mode regardless of the telephone communication. In the present embodiment, switching (S15) based on false detection (S13: Yes) can be prevented by sending VoIP call data in which the CNG component (1100 Hz) is cut.

As described above in detail, the communication device according to the first embodiment of the present invention has the following effects (1) to (7).
(1) Since the FAX codec I / F and VoIP codec I / F in the FAX modem control the FAX codec and VoIP codec, the load on the system side (host CPU) can be reduced.
(2) A general-purpose FAX codec and VoIP codec can be connected to the FAX modem.
(3) Since the FAX modem has a conversion function between the data handled by the FAX codec and the data handled by the VoIP codec, a VoIP call and a call using the general public network can be performed without providing a switch. it can.
(4) At the time of a call using the general public network, a signal level higher than that of the VoIP call is adjusted by a FAX modem in accordance with the characteristics of the general public network, thereby correcting the attenuation of the signal level when passing through the general public network. Call quality can be improved.
(5) Since the CNG component is removed from the VoIP transmission data by the FAX modem, it is possible to prevent malfunction of the TEL / FAX automatic switching of the communication apparatus that has received the transmission data.
(6) Since the FAX modem is equipped with a DAA control I / F and a telephone control I / F, compared to the configuration in which the DAA control and the telephone control are shared between the system side and the FAX modem side, the two control functions are integrated. Simple system configuration.
(7) Since DAA control and telephone I / F control can be performed simultaneously, VoIP call and G3 FAX communication can be performed simultaneously.

[Second Embodiment]
<Configuration of communication device>
FIG. 5 is a block diagram illustrating a configuration of a communication apparatus according to the second embodiment of this invention. In this figure, the same reference numerals as those in FIG. 1 are assigned to the same or corresponding parts as those in FIG. 1 (first embodiment).

  The communication apparatus according to the present embodiment includes a FAX / VoIP codec I / F 98 instead of the FAX codec I / F 94 and the VoIP codec I / F 95 in the first embodiment, and includes a DAA control I / F 96 and a telephone control. It has DAA / telephone control I / F99 instead of I / F97.

  The FAX / VoIP codec I / F 98 is a module that can selectively connect the FAX codec 10 and the VoIP codec 13, detect the connected codec, and perform an operation according to the codec. That is, when the FAX codec 10 is connected, it becomes a FAX codec I / F, and when the VoIP codec 13 is connected, it becomes a VoIP codec I / F.

  The DAA / telephone control I / F 99 is a module that can selectively connect the DAA 11 and the telephone I / F 14 and performs an operation according to the connection partner. That is, when the DAA 11 is connected, it becomes a DAA control I / F, and when the telephone I / F 14 is connected, it becomes a telephone control I / F.

  Here, since the DAA 11 is connected to the FAX codec 10, and the telephone I / F 14 is connected to the VoIP codec 13, the DAA 11 is connected if the FAX codec 10 is connected to the FAX / VoIP codec I / F 98. Is connected to the DAA / phone control I / F 99, and the VoIP codec 13 is connected to the FAX / VoIP codec I / F 98, the phone I / F 14 is connected to the DAA / phone control I / F 99.

<Fax / VoIP codec I / F>
FIG. 6 is a block diagram showing the internal configuration of the FAX / VoIP codec I / F 98 in FIG. 5, the connection relationship with the FAX codec 10 and the connection relationship with the VoIP codec 13. Here, FIG. 6A shows the case where the FAX codec 10 is connected, and FIG. 6B shows the case where the VoIP codec 13 is connected.

  The internal state of the FAX / VoIP codec I / F 98 in the FAX modem 9 and the connection relationship with the FAX codec 10 in FIG. 6A are the same as the internal state of the FAX codec I / F 94 and the connection with the FAX codec 10 in FIG. Same as relationship. That is, the internal state of the FAX / VoIP codec I / F 98 and the connection relationship with the FAX codec 10 are set so that the FAX codec 10 is a master and the FAX modem 9 side (SP / PS conversion register 981) is a slave. Is done.

  6B, the internal state of the FAX / VoIP codec I / F 98 in the FAX modem 9 and the connection relationship with the VoIP codec 13 are the same as the internal state of the VoIP codec I / F 95 and the VoIP codec 13 in FIG. It is the same as the connection relationship. That is, the internal state of the FAX / VoIP codec I / F 98 and the connection relationship with the VoIP codec 13 are set so that the FAX modem 9 side (internal timing generator 982) is a master and the VoIP codec 13 is a slave. The

<Automatic setting of internal state of codec I / F98 for FAX / VoIP>
As described above, the FAX / VoIP codec I / F 98 becomes a slave when the FAX codec 10 is connected, and becomes a master when the VoIP codec 13 is connected. That is, it is determined whether the FAX codec 10 is connected or the VoIP codec is connected, and switching is automatically performed based on the result. This switching operation will be described with reference to the flowchart shown in FIG. The processing of this flowchart is executed by a DSP (Digital Signal Processor) (not shown) in the FAX modem 9 when receiving a detection command from the host CPU 6.

  First, the internal timing generator 982 is set to stop the clock, and the bidirectional terminals T13 and T14 are set to the input mode (step S21), and it is determined whether or not SCK is detected by the SCK detector 983. (Step S22).

  When SCK is detected (step S22: Yes), it is determined that the connected codec has a master serial I / F (in this case, a FAX codec) (step S23), and the determination result is notified to the host CPU 6. (Step S24).

  On the other hand, if SCK is not detected (step S22: No), it is determined that the connected codec has a serial I / F that is a slave (here, a VoIP codec) (step S25), and the internal timing generator 982 is determined. Is set to generate a clock, and the bidirectional terminals T13 and T14 are set to the output mode (step S26). Then, the determination result is notified to the host CPU 6 (step S24).

  For automatic switching of the DAA / telephone control I / F 99, the DAA 11 is connected to the FAX codec 10, and the telephone I / F 14 is connected to the VoIP codec 13. Therefore, the FAX / VoIP codec I / F What is necessary is just to link with automatic switching of F98. Here, the DAA / telephone control I / F 99 does not switch between the master and the slave like the codec I / F 98 for FAX / VoIP, and the DAA control I / F and the telephone control I / F circuit other than the connection terminals. Are provided, and portions other than the connection terminal are alternatively connected to the connection terminal.

  Since the FAX modem 9 of this embodiment can be connected alternatively to the FAX codec 10 and the VoIP codec 13, a low-cost FAX modem with a small number of pins can be realized. Further, since it is automatically determined which of the FAX codec 10 and the VoIP codec 13 is connected and the internal state is set, the setting operation by the user becomes unnecessary.

[Third Embodiment]
FIG. 8 is a block diagram showing the configuration of the communication apparatus according to the third embodiment of the present invention. In this figure, the same reference numerals as those in FIG. 1 are assigned to the same or corresponding parts as those in FIG. 1 (first embodiment).

  The communication apparatus of the present embodiment includes an ISDN (Integrated Service Digital Network) codec 16 and an ISDN network I / F 17 instead of the VoIP codec 13 and the telephone I / F 14 in the first embodiment. Further, a modem unit 100 is provided instead of the modem unit 92 in the FAX modem 9. In addition to the function of the modem unit 92, the modem unit 100 includes FAX data and G.D. It has a conversion function with 711 encoded data, and is connected to a VoIP codec I / F 95 in addition to a FAX codec I / F 94. Since the telephone control I / F 97 in the FAX modem 9 is not used, it need not be provided. Note that the ISDN codec 16 has a serial I / F in which the codec is a slave, like the VoIP codec.

  This communication apparatus has a G3 FAX communication function and a G4 FAX communication function. Since signal processing of G3 FAX communication is the same as that in the first embodiment (FIG. 1), signal processing of G4 FAX communication will be described.

  The FAX data sent from the host CPU 6 to the FAX modem 9 is transmitted to the G.M. The data is converted to 711 encoded data, parallel-serial converted by the VoIP codec I / F 95, and serially output to the ISDN codec 16. Then, the ISDN data is converted into ISDN data by the ISDN codec 16 and sent to the ISDN network 18 through the ISDN network I / F 17.

  On the other hand, the ISDN data from the ISDN network 18 is input to the ISDN codec 16 through the ISDN network I / F 17. 711 encoded data. This G. 711 encoded data is serial-parallel converted by the VoIP codec I / F 95, demodulated into FAX data by the modem unit 100, and sent to the host CPU 6.

  According to the communication apparatus of this embodiment, G3 FAX communication and G4 FAX communication can be performed simultaneously. In the present embodiment, a VoIP codec may be added to configure a VoIP call. Also, the ISDN codec and the VoIP codec can be alternatively connected.

  DESCRIPTION OF SYMBOLS 9 ... FAX modem, 10 ... FAX codec, 13 ... VoIP codec, 92, 100 ... Modulator / demodulator, 93 ... VoIP data processor, 94 ... FAX codec I / F, 95 ... VoIP codec I / F, 96 ... DAA control I / F, 97 ... Telephone control I / F, 98 ... FAX / VoIP codec I / F, 99 ... DAA / Telephone control I / F.

JP 2004-147244 A (FIG. 8)

Claims (11)

A modem unit for facsimile data;
A VoIP data processing unit;
A modulation / demodulation apparatus comprising: a codec interface capable of connecting a codec for analog facsimile communication and a codec for VoIP. The modem according to claim 1, wherein
The codec interface is a modulation / demodulation apparatus including an analog facsimile codec interface capable of connecting an analog facsimile communication codec and a VoIP codec interface capable of connecting a VoIP codec. The modem according to claim 1, wherein
The codec interface is a modulation / demodulation device which is one codec interface capable of selectively connecting a codec for analog facsimile communication and a codec for VoIP. The modem according to claim 3, wherein
The codec interface is a modulation / demodulation device capable of switching functions according to a codec to be connected. The modem according to claim 4, wherein
Modulation / demodulation having codec discrimination means for discriminating whether the connected codec is a codec for analog facsimile communication or a VoIP codec, and means for switching the function of the codec interface according to the discrimination result of the codec discrimination means apparatus. The modem according to claim 1, wherein
It has a conversion means between the data format of the data handled by the VoIP codec and the data format of the data handled by the analog facsimile communication codec, and can transmit and receive data between the VoIP codec and the analog facsimile communication codec. Modem / demodulator. The modem according to claim 6, wherein
A modulation / demodulation device having means for performing signal level conversion according to a difference in characteristics between an analog public network and an IP network when format conversion is performed. The modem according to claim 1, wherein
A modulation / demodulation apparatus having a control I / F capable of connecting a DAA for analog facsimile communication and a telephone I / F for VoIP calls. The modem according to claim 1, wherein
A modulation / demodulation apparatus having means for removing CNG frequency components from VoIP data. The modem according to claim 1, wherein
The codec interface is a modem device capable of connecting an ISDN codec.   A communication apparatus comprising the modulation / demodulation apparatus according to claim 1.

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