Background technology
Gradually general along with high-speed Internet, (Voice over Internet Protocol, use VoIP) is also on the occasion of at that time for the networking telephone.Use the main benefit of the networking telephone to be, with utilize PSTN (public switched telephone network, PSTN) compare as the call rate of the black phone of talking path, utilize network as the call rate of the networking telephone of talking path will be cheaply how.Yet because the communication quality of the networking telephone and unstable, so modem of network telephone preferably possesses to switch to and utilizes the function of PSTN as talking path.Therefore, just arisen at the historic moment with the modem of network telephone of traditional PSTN as auxiliary talking path.The modem of network telephone of this type, its initial condition is configured to networking telephone pattern, just this moment, it utilized network as talking path, the user also can become the black phone pattern with the modem of network telephone manual switchover of the type, just utilizes PSTN as talking path.In addition, when the modem of network telephone of this type need be dialed an emergency number that is stored in especially in advance in this modem of network telephone, for example similarly be 119,110 etc., the modem of network telephone of this type need possess the function that can be switched to the black phone pattern automatically, just utilize more stable PSTN as talking path, rather than as networking telephone pattern still utilize network as talking path.When running into above-mentioned emergency, the modem of network telephone of this type will cut off being electrically connected between telephone set and a user loop interface circuit, then is electrically connected to PSTN, and dials this emergency number simultaneously automatically again.
Please refer to Fig. 1, Fig. 1 is the calcspar of the mode redialing system 10 of known modem of network telephone.One mechanical relay 20 is used for that a telephone set 12 optionally is electrically connected to a PSTN 22 or to a user loop interface circuit 14.User loop interface circuit 14 is used for the interface as analog telephone signal and networking telephone digital signal, is transmitted on network so that convert to data format as the data of this class of sound.Modem of network telephone mode redialing system 10 also comprises a transmitting-receiving testing circuit (off-hook and ring detect circuit) 18, it is electrically connected on PSTN 22 and is electrically connected to telephone set 12 by relay 20, is used to detect the ringing signal (incoming call) that transmitted from PSTN 22 and the receiver of telephone set 12 and links up with state (off-hookstatus).Modem of network telephone mode redialing system 10 also comprises dual-tone complex frequency coupling circuit (the dual tone multi-frequency redial coupling circuit that dials again, DTMFredial coupling circuit) 16, it is electrically connected between user loop interface circuit 14 and the PSTN 22, is used for dialing signal again is sent to PSTN 22 from user loop interface circuit 14.
When this networking telephone is not (for example, not online as yet) when being in the spendable state, relay 20 can be electrically connected to PSTN 22 with telephone set 12, and the phone that this moment, the user dialed can send out via PSTN 22; When this modem of network telephone was in the spendable state, relay 20 can be with telephone set 12 then is electrically connected to user loop interface circuit 14 so that utilize the function of the networking telephone.The user also can dial a predefined switching sign indicating number (predetermined code), for example similarly is that ' * * * * ' etc. are electrically connected to PSTN 22 with manual mode control relay 20 with telephone set 12.
The expense of modulator-demodulator is more cheap though dial network telephone, yet the communication quality of modem of network telephone is stable inadequately, any user should not wish dial important or emergency call in, phone breaks suddenly.For with traditional PSTN 22 as for the modem of network telephone of auxiliary talking path, when the user dial one be stored in especially in advance in this modem of network telephone telephone number the time, for example similarly be 119,110 etc., this modem of network telephone can be automatically then is utilized the passage of PSTN as conversation, and the telephone number that automatically redials the user and dialed delivers to PSTN, rather than as situation utilize the passage of network as conversation.The mode redialing system 10 that is to say modem of network telephone automatically control relay 20 is electrically connected to PSTN 22 and dialing again with telephone set 12.If the dialing mode that telephone set 12 is adopted is complex frequency type dialing mode (tone-dialing mode), then user loop interface circuit 14 can produce DTMF dialing signal again, and this signal is sent to PSTN 22 by the dual-tone complex frequency coupling circuit 16 that dials again.And in another kind of situation, if the dialing mode that telephone set 12 adopts is pulse dialing pattern (pulse-dialing mode), then relay 20 can be controlled so as to and disconnect apace and closed dial impulse with the generation correct number, and modem of network telephone mode redialing system 10 is exactly to utilize this mode to reach automatically the purpose of dialing again.
Above-mentioned system; its program that dials again is directly electrically connected at telephone set 12 to be finished under the situation of PSTN 22; that is to say; the user will hear the complex frequency type dialing or the incident sound that dials again of pulse dialing; the sound that this class is irritating, known modem of network telephone mode redialing system 10 users are perplexing in regular meeting.
Embodiment
Please refer to Fig. 2, Fig. 2 is the calcspar of the mode redialing system 30 of modem of network telephone of the present invention, the mode redialing system 30 of modem of network telephone comprises a user loop interface circuit 38, it is used for the interface as analog telephone signal and digital telephone signal, so that analog telephone signal form with data on network that this modem of network telephone is able to a telephone set 32 is sent transmits, when user loop interface circuit 38 receives a preset phone number when (this preset phone number meets the telephone number that is stored in advance in this modem of network telephone), it can produce again dialing signal and send it to a PSTN 42.The mode redialing system 30 of modem of network telephone also comprises one first relay 40, and it is preferably mechanical relay, is used for telephone set 32 optionally is electrically connected to PSTN 42 or arrives user loop interface circuit 38.The mode redialing system 30 of modem of network telephone also comprises a dummy load (dummy load) 48,1 second relay 50 and one the 3rd relay 36, and second and third relay 50,36 is preferably optocoupler close type relay (photo relay).Second relay 50 is electrically connected between PSTN 42 and the dummy load 48, be used for optionally setting up or cut off being electrically connected of PSTN 42 and 48 of dummy loads, the 3rd relay 36 is electrically connected between first relay 40 and the user loop interface circuit 38, is used for optionally setting up or cut off being electrically connected of first relay 40 and 38 of user loop interface circuits.The mode redialing system 30 of modem of network telephone also comprises two control circuits 52,34, and it is used for controlling respectively the change action of second and third relay 50,36.When dialing signal again produced, what second and third relay 50,36 was controlled to set up respectively PSTN 42 and 48 of dummy loads was electrically connected and cuts off being electrically connected of first relay 40 and 38 of user loop interface circuits.
The mode redialing system 30 of modem of network telephone also comprises a transmitting-receiving testing circuit 44, it is electrically connected on PSTN 42 and is electrically connected to telephone set 32 by first relay 40, is used to detect the receiver hook state of telephone set 32 and the ringing signal (incoming call) of the phone that sent from PSTN 42.The mode redialing system 30 of modem of network telephone also comprises the dual-tone complex frequency coupling circuit 46 that dials again, it is electrically connected between PSTN 42 and the user loop interface circuit 38, is used for that dialing signal again is coupled to transmitting-receiving testing circuit 44 and is used to isolate voltage between transmitting-receiving testing circuit 44 and the user loop interface circuit 38.
As known technology, when in case of emergency, this modem of network telephone preferably utilizes the more stable talking path of PSTN 42 these classes to transmit call-information, for instance, store a dialing rule or an emergency number (for example 110 in this modem of network telephone in advance, 119 etc.), when the user utilizes modem of network telephone to dial a phone, the number of this phone is if meet this dialing rule or emergency number, and this modem of network telephone will start again dial-up program and transmit passage to set up a framework in the new telephone signal of PSTN 42.
For the telephone set of adopting the complex frequency type dialing mode and for the telephone set of adopting the pulse dialing pattern, its program that dials again is different, no matter but adopt that a kind of dialing mode, this modem of network telephone all is to be set at network schemer at first, that is to say, first relay 40 is switched to telephone set 32 is electrically connected to user loop interface circuit 38, and the second other relay 50 disconnects (open's), and the 3rd relay 36 closures (close).
Please refer to Fig. 3, Fig. 3 adopts the quiet dual-tone complex frequency flow chart of dial-up program again of the telephone set of complex frequency type dialing mode for the present invention is used in:
Step 100: beginning;
Step 102: the user dials one with the dialing mode of complex frequency type and meets the number that is stored in the telephone number in this modem of network telephone, and dial-up program starts again;
Step 104: control circuit 52 is set second relay 50 state of closure (close) for, and dummy load 48 is electrically connected to PSTN 42, with the state (OFF-HOOK) that provides PSTN 42 to mention receiver;
Step 106: control circuit 34 is set the 3rd relay 36 state of disconnection (open) for, to cut off being electrically connected of telephone set 32 and 38 of user loop interface circuits;
Step 108: user loop interface circuit 38 produces dual-tone complex frequency dialing signal again again, and transfers the signal to the PSTN 42 by the dual-tone complex frequency coupling circuit 46 that dials again;
Step 110: first relay 40 is switched to telephone set 32 is electrically connected to PSTN 42;
Step 112: control circuit 34 is set the 3rd relay 36 state of closure (close) for, to set up being electrically connected of first relay 40 and 38 of user loop interface circuits;
Step 114: control circuit 52 is set second relay 50 state of disconnection (open) for, to cut off being electrically connected of dummy load 48 and 42 of PSTNs; And
Step 116: finish.
Note that step 112 and step 114 start from this again dialing signal all produce finish after, so modem of network telephone mode redialing system 30 could be reset into original set condition.
Please refer to Fig. 4, Fig. 4 adopts the quiet pulse flow chart of dial-up program again of the phone of pulse dialing pattern for the present invention is used in:
Step 200: beginning;
Step 202: the user dials one with the dialing mode of pulsed and meets the number that is stored in the telephone number in this modem of network telephone, and dial-up program starts again;
Step 204: control circuit 52 is controlled second relay 50 to produce the dial impulse signal again in mode closed again after repeating to disconnect, and transfer the signal to the PSTN 42, second relay 50 produces closure (close) state that is in later in this pulse dialing signal, dummy load 48 is electrically connected to PSTN 42, with the state (OFF-HOOK) that provides PSTN 42 to mention receiver;
Step 206: first relay 40 is switched to telephone set 32 is electrically connected to PSTN 42;
Step 208: control circuit 52 is set second relay 50 state of disconnection (open) for, to cut off being electrically connected of dummy load 48 and 42 of PSTNs; And
Step 210: finish.
Please note step 208 start from this again dialing signal all produce finish after, so modem of network telephone mode redialing system 30 could be reset into original set condition.
Compared to technique known, modem of network telephone mode redialing system 30 of the present invention utilizes second relay 50 and the 3rd relay 36 to control being electrically connected of telephone set 32 and 42 of PSTNs, meet when in advance being stored in the phone of the telephone number in this modem of network telephone when the user dials one, second relay, 50 closures (close) are to set up being electrically connected of dummy load 48 and 42 of PSTNs.In addition, when the complex frequency type dialing mode, the 3rd relay 36 disconnects (open) to cut off being electrically connected of telephone set 32 and 38 of user loop interface circuits.Because segregate between dialing signal and the telephone set 32 again, so the user can not hear the sound of this binary signal in dialling frequency multiplexed signal or when the dial impulse signal is sent to PSTN 42 again again.Then, after dialing signal is transmitted again, first relay 40 and second relay 50 just are switched to telephone set 32 are electrically connected to PSTN 42, arrive this, modem of network telephone mode redialing system 30 has just been finished the program of quiet dialing, and this program can prevent that the user is subjected to the interference of the dialing signal sound again.
The above only is the preferred embodiments of the present invention, and all equivalences of doing according to claim of the present invention change and improve, and all should belong to covering scope of the present invention.