Communication system having telephonic function

Abstract: A communication system having a telephonic function suitably adopted for a facsimile system, in which a telephone module includes: a call signal selecting circuit (l2) connected to a telephone line (10), for selecting and receiving station call signals; a key board (15) having input/output lines of two systems (L1d...L4a, L1e...L4e; L1...L4; L1a...L4a), one for outputting receiving station information to the call signal selecting circuit (l2) and another for a facsimile module (5); switches (P) interposed in lines between the key board (15) and the call signal selecting circuit (12), functioning so as to be shut off during the operation of the facsimile module (5) and to be con­ ductive during the non-operation thereof; third system lines indivi­ dually connected to lines (L1c...L4c) between the respective swit­ ches (P)and the call signal selecting circuit (12); and photocoup­ lers (P1...p4)for electrically isolating each of the third system lines during the non-operation of the facsimile module (5) and making the third system lines (L1c...L4c) conductive during the operation thereof, and for inputting the receiving station information to the call signal selecting circuit (12).

Description: The present invention relates to a communication terminal having a telephonic function and an alternative information transmitting function. The document JP-A-62065553 discloses a communication terminal having a telephonic function and an alternative information transmitting function, accordingly composed of a telephonic communication module and an information transmitting module, the telephonic communication module comprising: call signal selecting means for selecting a receiving station call signal to be connected to a telephone line; input operating means having a first system of output lines connected to the call signal selecting means and a second system of output lines connected to the information transmitting module, for outputting a receiving station's information through the output lines in the first and second systems; change-over means interposed with its first input terminals and output terminals in the output lines of the first system which change-over means functions so as to disconnect the lines from the call signal selecting means when receiving an operative signal from the information transmitting module and to connect the lines when receiving a non-operative signal from the information transmitting module; a third system of input lines connected to the second input terminals of the change-over means such that receiving station's information from the information transmitting module is inputted to the third system and is fed to the input terminals of the call signal selecting means in case that the change-over means receives a control signal corresponding to the information transmitting module being operative. It is the object of the present invention to define a communication terminal providing for electrical isolation between the elements of the telephonic communication module and the information transmitting module at times when the latter module is not operative, e. g. due to an interruption in the power supply. This object is solved by a terminal having the features of appended claim 1. In this terminal, the information transmitting module can be isolated electrically from the telephonic communication module, when the information transmitting module is not operating, and it is also possible to prevent noise from entering the telephone line. Other objects and advantages of the invention will becomes more apparent during the following discussion with reference to the accompanying drawings. FIG. 1 is a block diagram illustrating the fundamental construction of the call signal generating unit which is the principal part of a facsimile system in embodiments of the present invention; and FIG. 2 is a perspective view illustrating the external appearance of the embodiments of the present invention. FIG. 1 illustrates a telephone-built-in facsimile system 1 developed as a communication terminal having a telephonic function. The facsimile system 1 essentially consists of a telephone module 2 and a facsimile module 5. A telephone line 10 is connected to the telephone module 2 (defined as the telephonic communication module) and is also connected through a relay unit 3 and a transformer 4 to a facsimile module 5 (defined as the information transmitting module). The relay unit 3 is so driven as to be conductive when the facsimile module 5 allows the use of the facsimile system 1 for facsimile communication. At this time, the facsimile system 1 cannot be employed for telephonic communication. The telephone module 2 incorporates a pulse generating circuit 7 for generating a DP (Dial impulse) signal when using a dial line and a PB (push button) signal when using a push-button dial telephone line, and a telephonic communication circuit 8 to which a hand set 9 is connected. A change-over switch (not illustrated) serves to trigger the DP signal/PB signal change-over on the signals generated by the pulse generating circuit 7. A rectrifier circuit 6 is connected to a power source circuit 11 for taking electric power out of the telephone line 10 and supplying the operating electric power via lines 13 and 14 to a selection signal generating unit 12, conceived as the call signal selecting means. The selection signal generating unit 12 generates a predetermined signal when an operator manipulates an operation panel 15 defined as input operating means. This signal is transmitted via line 16 to the pulse generating circuit 7. The power source circuit 11 takes its electric power from the telephone line 10 and is therefore capable of providing the selection signal generating unit 12 with the electric power even in the case of power suspension. The pulse generating circuit 7 and the selection signal generating unit 12 are both combined to form the dialling means. The operation panel 15 is composed of a key board having a plurality of keys arranged in matrix and two separate systems of input and output lines. Totally 16 pieces of contacts S1 to S16 are provided at intersections between input lines L1d to L4d and output lines L1e to L4e of the first system of lines. Similarly, 16 pieces of contacts S17 to S32 are provided at intersections between input lines L1 to L4 and output lines L1a to L4a of the second system of lines. The contacts Sn and Sn+16 cooperate to constitute a dual switching mechanism which is simultaneously opened or closed by operating the corresponding n th common key. From the thus constituted operation panel 15 the signals can be outputted in 16 different kind of ways. The input lines L1d to L4d of the first system are connected to the selection signal generating unit 12, while the output lines L1e to L4e are connected to an analog switch 17 serving as the change-over means. The input lines L1 to L4 of the second system are connected to the facsimile module 5, and the output lines L1a to L4a are likewise connected to the facsimile module 5. The analog switch 17 is connected via the common lines L1c to L4c to the selection signal generating unit 12 and is further connected through a photo-transistor Q to line 14. A light emitting diode D is disposed corresponding to the photo-transistor Q, and the diode D and the transistor Q are combined to form a photocoupler P. When power is supplied to the facsimile module 5, the light emitting diode D remains conductive, and hence the photo-transistor Q is also in the conductive state. The analog switch 17 shuts off during the conduction of the photo-transistor Q but is made conductive when the transistor Q shuts off. The common lines L1c to L4c are respectively connected via photo-transistors Q1 to Q4 defined as the switching means to the line 14. Light emitting diodes D1 to D4 are disposed corresponding to the photo-transistors Q1 to Q4, which cooperate to constitute photocouplers P1 to P4. Signals conceived as receiving station information are imparted from the facsimile module 5 via lines L1b to L4b, which serve as third input lines, to the light emitting diodes D1 to D4, thereby controlling their conduction and shut-off. When the light emitting diodes D1 to D4 are made conductive or shut off, the photo-transistors Q1 to Q4 are concomitantly made conductive or shut off. The lines L1b to L4b are provided so as to correspond to the lines L1a to L4a of the second system. Hence, if the signal is led to, for instance, the output line L2a, the facsimile module 5 correspondingly outputs the signal to the line L2b, thus making the light emitting diode D2 conductive. As a result of this, the photo-transistor Q2 is also put into the conductive state, and it follows that the signal is led to the common line L2c. The selection signal generating unit 12 generates selection signals corresponding both to the signals parallelly given to the input lines L1d to L4d of the first system and to the signals parallelly given from the common lines L1c to L4c, and imparts these selection signals to the pulse generating circuit 7. Subsequently, the pulse generating circuit 7 generates DP/PB signals corresponding to the thus imparted signals. While power is supplied to the facsimile module 5 (input/output lines of the second system are used), the analog switch 17, as described above, shuts off, and therefore the output lines L1e to L4e of the first system are not connected to the common lines L1c to L4c. The signals supplied via the common lines L1c to L4c to the selection signal generating unit 12 are signals obtained from the photocouplers P1 to P4. It is thus possible to establish the electrically conductive state between the facsimile module 5 and the telephone module 2 with the aid of the analog switch 17 and the photocouplers P1 to P4. During power suspension of the information transmitting module (input/output lines of the first system are used), the light emitting diode D is shut off, at which time the analog switch 17 conducts electricity while the relay unit 3 is shut off. When the analog switch 17 comes into the conductive state, the operation panel 15 transmits the signals through the lines L1d to L4d, the lines L1e to L4e and the common lines L1c to L4c to the selection signal generating unit 12. The relay unit 3 is then shut off, whereby the facsimile system 1 comes to have a telephonic function alone. In this case, when a call number is inputted by operating the operation panel 15, the selection signal generating unit 12 outputs a signal corresponding to the inputted call number to the pulse generating circuit 7. The pulse generating circuit 7 in turn generates the corresponding DP/PB signal. When the line is connected to a telephone (not illustrated) of the receiving station, the telephonic communication may be provided by use of the hand set 9. Where the communication terminal is utilized as a facsimile at the power source supplying time, the call number of the receiving station is inputted by operating the operation panel 15. Then, the signals are imparted via the input lines L1 to L4 of the second system of lines, the output lines L1a to L4a, the facsimile module 5, the lines L1b to L4b, the photcouplers P1 to P4 and the common lines L1c to L4c to the selection signal generating unit 12. The selection signal generating unit 12 outputs the signal corresponding to the inputted call number to the pulse generating circuit 7. The pulse generating circuit 7 generates the DP/PB signal corresponding to the thus outputted signal. On connecting the line to a receiving facsimile terminal (not shown), the facsimile module 5 initiates the transmission of a manuscript. In the embodiment given above, the analog switch 17 is shut off when inputting the power source, and the signals corresponding to the receiving station information are inputted via the input/output lines of the second system of lines, the facsimile module 5 and the photocouplers P1 through P4 to the selection signal generating unit 12. At this time, the conductive state between the facsimile module 5 and the telephone module 2 is established. When power suspension occurs,the analog switch 17 is made conductive, and the signals are inputted via the input/output lines of the first system of lines, the analog switch 17 and the common lines L1c through L4c to the selection signal generating unit 12. Even in the case of power suspension, the facsimile system 1 is capable of performing its telephonic function, and is at the same time electrically isolating the telephone module 2 from the facsimile module 5. On the basis of the above-described constitution, the dialing means of the facsimile module 5 can be shared with the telephone module 2. This results in a reduction in manufacturing cost for the facsimile system 1. If power suspension occurs, the facsimile module 5 is electrically isolated when employing the telephone, so that it is feasible to prevent noises from entering the telephone line. Note that FIG. 2 illustrates an external appearance of the facsimile system 1, wherein the numeral 9 designates a hand set and 15 represents a key input unit serving as input operating means.

Claims: A communication terminal having a telephonic function and an alternative information transmitting function, composed of a telephonic communication module (2) and an information transmitting module (5) in which the telephonic communication module comprises: call signal selecting means (12) for selecting a receiving station call signal to be generated and inputted to a telephone line (10), input operating means (15) having a plurality of keys arranged in a matrix, each of the keys acting on an associated first and an associated second switch (S1/S17, S2/S18, ...) which are electrically isolated from each other, the respective plurality of first switches (S1...S16) being capable of interconnecting input lines (L1d...L4d) and output lines (L1e...L4e) of a first system of input/output lines connected to the call signal selecting means (12) and the respective plurality of second switches (S17...S32) being capable of interconnecting input lines (L1...L4) and output lines (L1a...L4a) of a second system of input/output lines, the output lines of the first system of input/output lines being connected to the call signal selecting means (12) by interposition of a corresponding plurality of common lines (L1c...L4c), the second system of input/output lines being connected to the information transmitting module (5), the input operating means (15) and said first and second systems of lines being provided for outputting a receiving station's information through the output lines in the first and second systems, a first switching means (17) interposed between the output lines (L1e...L4e) of the first system and said common lines (L1c...L4c) which first switching means passes to the interrupted state when receiving a control signal from the information transmitting module (5) indicating the operative state thereof, and passes to the connected state when the received control signal indicates the non-operative state of the information transmitting module, the module being electrically isolated from the switching means, a third system of input lines (L1b...L4b) connecting the information transmitting module (5) to said common lines (L1c...L4c) for inputting a receiving station's information from the module to the call signal selecting means (12), a plurality of second switching means (P1...P4) interposed in the third system of input lines (L1b...L4b) for disconnecting and electrically isolating the information transmitting module (5) from the call signal selecting means (12) in case the module (5) is non-operative and for connecting the module to the means (12) when the module is operative. A communication terminal as claimed in claim 1, in which the first switching means (17) is composed of photocoupler switches each consisting of a light emitting diode and a photo-transistor. A communication terminal as claimed in claim 1, in which each of the second switching means (P1...P4) is composed of a photocoupler consisting of a light emitting diode (D1...D4) and a photo-transistor (Q1...Q4).

Inventors: HAYASHI MOTOHIKO, KOTANI MATAHIRA, HAYASHI, MOTOHIKO, KOTANI, MATAHIRA
Applicants: SHARP KK, SHARP KABUSHIKI KAISHA
Application year: 1988
Main classification: H04N1
IPC codes: H04N1, H04M1, H04M11