MXPA00000888A - Security system alarm panel - Google Patents

Abstract

The invention provides an alarm panel connected to a telephone line. The alarm panel comprises a microprocessor connected to a circuit which operates in two states:passive and active. In the passive state, the alarm panel monitors the line for a ring signal and tests the integrity of the telephone line. In the active state, the alarm panel seizes the telephone line and provides full bi-directional communication with a receiver through the telephone line. The circuit is designed such that the individual subcircuits for each state operate independently of each other and can be modified to meet various regulatory requirements without affecting the other circuits. The circuit draws low current in the passive state. Finally, the circuit is separated from the microprocessor using only 2 or 3 optocouplers,

Description

ALARM BOARD OF SECURITY SYSTEM FIELD OF THE INVENTION The present invention is directed to alarm panels for security systems and in particular, refers to alarm panels having a microprocessor and an associated communication configuration for contacting a monitoring station using the telephone system.

BACKGROUND OF THE INVENTION An alarm panel receives signals from a main sensor exchange and processes these signals to determine if an alarm condition or other event has to be reported. The alarm panel is typically connected to a telephone line and uses this line to report the alarm condition or any event that must be reported to a control station. Normally the telephone line is shared between the alarm panel and other downstream telephone devices, but the alarm panel has priority and the ability to interrupt the communications of the downstream devices. The patent of E.U.A. No. 4 262 283 of Chamberlain and the patent of E.U.A. No. 3 982 242 of Sheffield are examples of specialized alarm systems that communicate with central stations using telephone lines. The patent of E.U.A. No. 4 262 283 requires a scan configuration in local exchanges to receive and route alarm signals from the control panel. The patent of E.U.A. No. 3 982 242 is a specialized configuration that uses a McCulloh loop to allow various alarm systems to share a shared line. These patents are examples of a main plant of systems of the prior art that define the general state of the art and that are not of particular relevance to the present invention. Public telephony systems vary and different regulatory bodies have developed their own specifications that alarm panels and other devices must meet to be approved. These different specifications are not easily met with a single cost-effective circuit and different circuits have been developed to meet different regulatory specifications. Separate designs for each different market increase manufacturing costs and limit manufacturing flexibility. In France, for example, the standard requires that the output current of the device have a limit between 25 and 60 mA. In contrast, in the requirements for the United States and Canada it is not necessary that the circuit has a current limit. As will be explained in more detail, an alarm panel switches between a passive state and an active state. In the active state, the alarm panel uses the telephone line to establish communication with a remote computer to communicate, for example, with the owner at a remote location. In the passive state, the alarm panel monitors the telephone line to identify a call signal and may also perform tests to determine the integrity of the line. The control panels of the prior art have used 4 or 5 optocouplers to electrically isolate the microprocessor from the telephone line alarm panel. It is also known how to use only two optocouplers to isolate the microprocessor from the telephone line alarm panel; however, this design of two optocouplers greatly compromises the operating characteristics of the same.

BRIEF DESCRIPTION OF THE INVENTION A security alarm panel of a security system, in accordance with the present invention, comprises a microprocessor for processing signals from security sensors and, appropriately, communicating with a remote computer from time to time, using a telephone line connection . A receiving optocoupler and a transmission optocoupler are part of a communication circuit that connects the microprocessor with the telephone line connection whose circuit receives power from the telephone line. The optocouplers of reception and transmission electrically isolate the microprocessor of the communication circuit, which is directly connected to the telephone line. The communication circuit includes two sub-circuits connected to the telephone line connection. These subcircuits are a subcircuit for detecting the CA call signal and an active communication subcircuit, each of which shares the reception optocoupler. The active communication subcircuit operates in an inactive state or an active state. In the inactive state, the telephone line is separated from the communication subcircuit by a large resistor and there is a low output current. In the active state, the line is taken and the alarm panel generates off-hook signals. The large resistance is diverted and full two-way communication via the telephone line is possible. In this state there is a much higher current output. The CA call signal detection subcircuit monitors the telephone line connection to detect a call signal and the signal passes to the microprocessor. The communication subcircuit CD cooperates with the microprocessor to produce a hang-up condition allowing the microprocessor to form a two-way communication through the optocouplers and the telephone line connection when the microprocessor provides an off-hook signal to the DC communication subcircuit. through the transmission optocoupler. The AC ring detection subcircuit is designed to be independent of the DC voltage, have a lower power consumption and is designed to pass the AC component of the telephone call signal to the receiving optocoupler. The communication subcircuit is designed to determine the DC current characteristics of the communication circuit when the circuit has taken the line and the line has moved to a "off-hook" state. The call signal detection feature can be modified by varying the CA call signal detection subcircuit without any noticeable effect on the communication subcircuit. The power consumption and the DC voltage characteristics of the communication circuit can be modified by changing the components without any noticeable effect on the call signal detection characteristics of the CA call signal detection subcircuit. The alarm panel, as defined above, can easily be customized by modifying the communication subcircuit without disturbing the call signal detection subcircuit, still allowing subcircuits to share the receive optocoupler. In this way, modifications can be made to any of the subcircuits to cover any particular standard and these modifications do not change the characteristics of the other subcircuit. This provides a great flexibility that allows the individual components of the subcircuits to be changed to cover the specific requirements. In accordance with a preferred aspect of the invention, the communication subcircuit includes telephone line monitoring to determine whether the telephone line is operable. For example, the telephone line can be cut off and, if it is the case, it will be useful for the alarm panel to receive information about this service interruption. The telephone line monitoring configuration includes a charging device in the communication subcircuit which is charged by a low current in the subcircuit in the inactive state. The charging device is selectively discharged by the microprocessor, producing and transmitting a signal or series of signals through the transmission optocoupler. When the microprocessor transmits a signal, it results in a discharge of the loaded device, which produces a discharge signal that is supplied to the microprocessor through the receiving optocoupler. If the telephone line is not active, the charging device does not charge and does not produce a discharge signal. Failure to detect such a discharge signal indicates to the microprocessor that the telephone line is not available. In accordance with a further aspect of the invention, the subcircuits are joined in the telephone line connector and in a common section that includes the receiving optocoupler. In accordance with a further aspect of the invention, the communication subcircuit includes a power dissipation configuration, which, in the case of a transient high voltage condition, dissipates the energy and limits the current in the subcircuit to a maximum, before reaching the maximum transient voltage.

BRIEF DESCRIPTION OF THE DRAWINGS Preferred embodiments of the invention are shown in the drawings, in which: Figure 1 is a schematic view of a security system including a central panel.

Figure 2 illustrates a simplified circuit diagram of the communication configuration of a control panel. Figures 3A, 3B, 3C and 3D illustrate a circuit diagram of the communication configuration of an alarm panel; and Figures 4A, 4B, 4C and 4D illustrate a circuit diagram of a preferred embodiment of the communication configuration of an alarm panel.

DETAILED DESCRIPTION OF THE PREFERRED MODALITIES Figure 1 shows a typical control panel 300 associated with the telephone service 302 that connects the control panel to a public switched telephone network 304. The control panel 300 is typically installed in a house or other premise identified as 306 and has a series of sensors 308 properly distributed to provide monitoring of the premise. These sensors are in communication with the control panel 300. The control panel 300 receives the signals from the sensors and processes these signals to determine if an alarm condition exists. When the determination of an alarm condition exists, the control panel typically takes the telephone line 302 and communicates this alarm condition to a remote security monitoring station which is shown as 310. Most of the control panels 300 share the telephone line 302 with additional telephone devices indicated as 312 located within premise 306. The control panel is placed between these devices 312 and telephone line 302 in such a way that the control panel can take the line at any time and communicate with a security monitoring station or other agencies such as a police station, fire department, ambulances, these being some examples. It is also desirable for an alarm panel to answer certain incoming calls. For example, some alarm panels have the feature that the owner can access them remotely through the telephone system. Some control panels are designed to respond after a predetermined number of rings or after a second communication immediately following a first communication. With configurations of this type, the control panel must recognize and monitor incoming telephone signals. It is also desirable to monitor the telephone lines 302 to determine if it is operative, as is known, to cut the telephone line in an effort to override the security system. The alarm panel preferably monitors the telephone line to determine when it has been cut or is not available. The above functions of a control panel are already known, however, the present invention provides a simple way to effectively isolate the microprocessor from the telephone service control panel cost-effectively, and additionally provides a circuit design that can be modified to cover the different requirements of different normative bodies. As discussed above, various telephone regulatory bodies impose different electrical response characteristics for devices, including alarm panels, connected to the respective telephone systems. In particular, certain response characteristics must be covered when the alarm panel is connected to the line and when the telephone line is taken. The present design allows a convenient modification of the control panel to cover different requirements of different regulatory bodies. In addition, the circuit allows sharing the functions of the reception optocoupler to reduce the overall cost of the circuit. To achieve these results, the communications configuration 300 of the control panel is designed to operate in two different states: a passive standby state and an active state. In the passive standby state the communications configuration does not use the telephone service 302 and the downstream telephone devices indicated as 312 may use the service as normal. The communications configuration has the capacity, at any time, to disconnect the 312 devices from the telephone service and take the line so that the control panel reports an alarm or other security condition on the telephone line. When the control panel is in passive state, the telephone line may be in use by one of the 312 devices or the telephone line remains available for use by any of the devices. When the telephone line is available and even when the telephone line is in use by one of the devices, there is a voltage on the telephone line and 1 This voltage can be used to indicate whether the telephone service is available for use. It is desirable for the control panel to monitor the telephone line while keeping the line available for normal use. This communications configuration enters the active state upon recognition of an alarm condition or an event that must be informed. In the active state, the control panel 1) takes the line if the line is in use and disconnects the communication and then initiates an outgoing communication on the telephone line, or 2) takes the telephone line isolating the telephone 312 devices from the service and causes the telephone line to be in off-hook state, and initiates outgoing telephone communication. The present circuit has a low output current of less than 20 μA and maintains excellent call signal sensitivity. This is accomplished by dividing the incoming telephone signal to produce a signal for call signal detection and a rectified signal for communication. With reference to Figures 2, 3A, 3B, 3C and 3D, more details about the circuit operation in its two states can be observed. The operation of the alarm panel circuit in each state will be described at the time. Figure 2 shows the communication configuration 400 of the communication configuration operating in the passive state. The communication configuration 400 is shown with lines 470 and 472 connected to the telephone system and the home telephones are generally shown connected to 473 and 474. The line tap switches 402 and 404 are shown in the normal position and connect the lines 470, 472 to 473, 474. In this state, domestic telephone devices can function normally. In the passive state, two separate circuits can be observed. The first circuit provides telephone line integrity monitoring and the second provides call signal detection. The signals of the lines 470 and 472 are immediately divided before the large resistors 440 and 442. The signals after the large resistors are connected to the line integrity monitoring circuit. In the modality that is described, the resistance of each one is 2 x 107 ohms. The bridge rectifier 444 is separated from the lines 470, 472 by resistors 440 and 442. These resistors limit the signal that passes to the bridge rectifier 444 and provides a very low output current from the circuit. Many telephone companies have imposed a maximum output current for telephone devices of 10 μA when the line has not been taken. In the line integrity monitoring circuit, a communications subcircuit is provided to monitor the integrity of the telephone line. This is achieved by charging a capacitor on the subcircuit using the voltage on the subcircuit of the telephone line and periodically taking samples of the voltage stored therein. The capacitor is charged through large resistors, which restricts the current leaving the telephone line below 10 μA, when it is in the passive state. A sample of the capacitor voltage is taken periodically when the microprocessor issues a telephone line monitoring (TLM) pulse. This pulse activates the transmission optocoupler, which in this way completes a loopback circuit for the capacitor. Any voltage stored in the capacitor produces a discharge current, which flows through the receiving optocoupler. The microprocessor examines any current flowing through the receiving optocoupler. If the telephone line is cut off, the load on the capacitor dissipates. As a result, the microprocessor does not receive pulses through the receiving optocoupler, thus indicating a cut or failure in the telephone line. The microprocessor 420 controls the transmission optocoupler 418. The microprocessor can send a telephone line monitoring pulse to the transmission optocoupler 418 as shown as signal 450. When this signal is supplied to the transmission optocoupler, this leads, in this way completing the subcircuit with the capacitor 430. In this way, the capacitor 430 discharges, producing the signal indicated as 454. The resulting current activates the receiving optocoupler 416. This causes the level control circuitry generate a pulse that the microprocessor receives. In such a way, if the telephone line is working properly, when the microprocessor generates a telephone line monitoring pulse 452, the microprocessor must receive a response pulse due to the signal 454 produced by the storage capacitor discharge 430. If not response pulse is detected, that is, there is no current flow through the receiving optocoupler, the microprocessor assumes that the telephone line has a problem or has been disconnected. The microprocessor emits these telephone line monitoring pulses at a predetermined regular frequency, and in this way, the microprocessor continuously monitors the integrity of the telephone line. Figures 3A, 3B, 3C and 3D show aspects of the TLM circuit in greater detail. The TLM circuit is charged with a low current DC signal passed through the resistors 28 and 29. In the passive standby state the slow current flows from the telephone line to the capacitor 12, and charges it. Eventually, the capacitor 12 is fully charged, presenting a high CD resistance to the signals at 32. When the microprocessor tests the integrity of the telephone line, it forces the TLM signal line 7 low. At the time, the transistor 34 and the op amp 33 drift the signal and cause the optocoupler 10 to drive. Therefore, any voltage stored in the capacitor 12 is discharged in series through the optocouplers 9, 10 and the resistor 30. When the current flows through the optocoupler 9 it conducts and generates a signal. The signal is derived by transistor 36 and resistor 35 and sent to the input that monitors TLM of the microprocessor. While the voltage stored in the capacitor 12 leaves the current from the capacitor 12 through the optocoupler 9, it decreases. At some point, the optocoupler diode 9 stops driving and the microprocessor does not receive any TLM signal. When the microprocessor forces the line signal TLM 7 high, the discharge loopback for the circuit is broken and the capacitor 12 can be charged again as was done before. If the telephone line has been disconnected, then there is no source voltage to charge the capacitor 12. As it is possible for the capacitor 12 to charge and then disconnect the line, a first TLM signal is sent through the circuit to discharge the initial voltages stored in the capacitor 12. Subsequently, a second TLM signal is generated to determine if the capacitor 12 has been recharged. If the telephone line has been disconnected, the capacitor 12 is not reloaded and a second TLM detection signal can not be generated. The microprocessor shows this signal at regular intervals. In the passive waiting state, the first circuit uses large resistors to reduce the output current. This low output current inherently degrades the sensitivity of the first circuit to detect a call signal on the telephone line. To cope with the above, a second circuit in a passive standby state provides a call signal detection on the telephone line. In the call signal detection circuit, the signals of the lines 470 and 472 are divided to deflect the large resistors of the first circuit. The second circuit monitors only the AC component of the telephone line signals, thus presenting only a minimal effect on the output current. In this design, the circuit usefully reduces the output current until a call signal is detected or the microprocessor 80 takes the line for another reason. For example, the microprocessor 80 may send an initiation signal to the alarm receiver. Useful, the processed call detection signal is fed to the same receiving optocoupler of the first circuit, thereby reducing the total number of circuit components. With reference to Figure 2, the call signal detection circuit of the passive standby state circuit has lines 406 and 408; the capacitors 407 and 409 do not pass the CD portion of the telephone signal through the lines. Meanwhile, the AC portion of the signal passes to the ring sensitivity device 410. This device queries the CA signal provided to it and determines whether a ring signal is present. It can pass each of the pulses of the ringing signal or it can produce a separate signal indicated as 414, which is provided on line 412 to the receiving optocoupler 416. When a ringing signal CA is present and deflects forward the receiving optocoupler 416, the receiving optocoupler generates a call detection signal, which is provided to the microprocessor. In response to a call detection signal, the microprocessor sends a signal to activate the switches 402 and 404, causing it to reverse its position. In the reverse position, the domestic telephone devices are cut from the telephone system and furthermore, a deviation has been provided past the large resistors 440 and 442. In this way, the normal telephone signal is provided to the bridge rectifier 444.

Figures 3A through 3D provide more details about the call signal detection circuit. The circuit comprises a call signal terminal 1, capacitor 20, resistor 21, optocoupler 9, diode 11, metal-oxide varistor ("MOV") 24, resistor 23 and capacitor 22, and tip 2. MOV 24 provides sensitivity of call sign for the circuit and is chosen to provide specific voltage sensitivity responses. The call signal detection circuit operates as indicated below. When a CA call signal is present on the telephone line, the AC signal flows freely through the resistor 21 and capacitor 20 towards the optocoupler 9. The capacitor 20 blocks the CD component of the signal from the circuit remnant. The AC signal causes the internal transistor of the optocoupler 9 to drive. The AC signal continues from the optocoupler through MOV 24, through the resistor 23 and capacitor 22, and exits through the tip 2. For the generation of a call detection signal, the internal optocoupler transistor 9 is connected to two activation resistors 38 and 39 to the power voltage. As such, when the internal transistor conducts, the collector of the internal transistor is attracted towards the energy voltage. This forces the transistor 36 to drive, thus initiating a low signal to be sent to the microprocessor. This low signal indicates that a call signal pulse was detected on the line. This signal is generated for each positive portion of the call signal CA. In this way, the call detection signal 8 sent to the microprocessor 80 is a burst of pulses.

With reference to Figure 2, the call signal sensitivity device 410 may be designed to provide a desired call signal sensitivity, since it is completely separate from the bridge rectifier 444, and in particular, separate from the large resistors 440 and 442. Furthermore, since the call signal detection circuit is isolated from the rest of the circuit through the large resistors, it can be modified without affecting the operation characteristics of the other circuits. As described above, when the alarm panel responds to an incoming call or needs to initiate telephone communications with the receiver, the circuit changes to the active state. The alarm panel may need to initiate telephone communications in response to signals received from its various security sensors. Figure 2 illustrates aspects of the alarm panel operating in the active state. In this state, the telephone line is taken from the downstream telephone devices by activating the hook switch and the line tap relay. The hook switch is activated when the microprocessor produces an off hook signal 450 and the transmission optocoupler 418 drives. The line tap relay switches 402 and 404 are placed in the active position by the microprocessor. The active position is the opposite position shown in Figure 2. With switches 402 and 404 in active position, telephone signals are diverted from resistors 440 and 442 and thus a non-attenuated telephone line signal is provided to the bridge rectifier 444. In this way, in the active state, the microprocessor can transmit non-attenuated signals over the telephone lines and receive non-attenuated signals through the reception optocoupler 416. The telephone line must have a DC resistance and an AC impedance as the specifications established by the telephony regulatory bodies of each country. A current source proportional to the incoming telephone line voltage is sent to represent the CD resistance required by the specific telephone company, including those that require a current limit of less than 60 mA under all line conditions. The AC impedance of current sources is much higher than the impedance of 600 ohms in such a way that it will not interfere with the ZL value or complex impedance specified by telephone companies. The AC signal of the telephone line is established through ZL (600 ohms or complex impedance) since it is coupled to the receiver optocoupler to AC. The input signals from the input optocoupler pass to the microprocessor after signal conditioning and evaluation. The output signals modulate the telephone line current by means of the output optocoupler. The base emitter junction of the hanging switch and the input optocoupler diode, both are of low impedance for AC signals, thus they do not prevent the modulation of the telephone loop current. Figures 3A to 3D provide more details about the circuit operation in active state.

In the active state, the microprocessor 80 generates an off-hook signal 7. In the present embodiment, the signal is active low. The transistor 34 and the op-amp circuit 33 are connected to an optocoupler 10. When the off-hook signal 7 is forced down, optocoupler 10 conducts, thereby initiating 31 hook switch transistor 15. A telephone signal circuit Active AC allows the panel to send and receive undamaged AC signals over the telephone line. The active AC circuit comprises the bridge rectifier diodes 3, 4, 5 and 6, the receiver optocoupler 9, the transmission optacoupler 10, the capacitors 18 and 19, resistors 16 and 17, off-hook transistors 15. The capacitor network 18 and 19 and resistors 16 and 17 provide the complex impedance characteristics of the circuit when operating in active state. The signals generated by the ASIC are injected into the telephone line signal through op-amp 33 and transmission optocoupler 10. These injected signals flow through resistors 30 and 31 to the bridge rectifier, and out of circuit. The CD operating characteristics of the active state circuit provide defined voltage current characteristics to meet the regulatory requirements of various countries. When the hook switch 15 is active, the DC current flows through the rectifier bridge of the diodes 3, 4, 5 and 6, subsequently through the resistors 27 and 26. When the active voltage CD increases, the transistor 25 provides a greater DC current to the circuit in active state. The DC current flows through transistor 25 through the hook switch transistor 15 and out of the jumper switch.

Furthermore, in the active state, the signals that would normally flow through the call signal detection circuit CA divert the circuit through the neon lamp 44. In such a way that, in the active state, the receiving optocoupler 9 it will react only to the signals that are present in the active AC circuit. It can be seen that various circuits can be used in place of transistors 25 to provide different current voltage output characteristics. For example, in Figure 4, transistors 225, 254, 255 and 256 and resistors 226, 235, 257 and 258 establish a stepped network of transistors providing an active DC current output characteristic suitable for the Scandinavian countries. In another configuration, the Zener diode 261 provides limited current response characteristics in accordance with the requirements of the French regulations. When the DC voltage increases in the telephone line, the Zener diode 261 secures the voltage at the base of the transistor 225, thus limiting the current output of the circuit in the active state. Another feature of the present invention is that it provides a single circuit card that can be used for different manufacturing structures of the alarm panel. For example, the manufacturing structure for a French alarm panel will use the same circuit board for a structure of an American alarm panel. By using the same card, manufacturing costs are reduced.

The figures from 4A to 4D show aspects of the circuit required to provide different manufacturing structures on a circuit board. In the embodiment described, a particular card configuration is chosen by simply diverting one section of the circuit to another. To achieve this flexibility, an optocoupler 250, and 0 ohm resistors 251 and 252 are provided. The configuration is chosen by filling the card with resistors 251 or resistors 252. When the resistor 251 is filled on the card the current response characteristics of The voltage of the circuit is governed by the configuration circuit comprising the Darlington transistors 215, transistors 225, 254, 255 and 256, resistors 226, 235, 257, 258, 259, 260, 262, 263, 264, 265, capacitors 219 and 266 and Zener diode 261. When the resistor 252 is filled, the previously observed configuration circuit is biased with the transistors 225 and 215 and the resistors 231 and 262 forming the circuit in active mode. From the foregoing, it can be seen that the division of the circuit with these separate subcircuits allows a low output current in a generally passive state, while allowing a complete signal to be transmitted in an active state. These subcircuits usefully share a single transmission optocoupler. The design allows the standardization of a common circuit card for many countries and also allows the circuit card to be customized by changing the particular values of the individual components to meet the requirements in different countries. This advantage is possible due to the separation of the signals as analyzed. From the foregoing, it can also be seen that the ring detecting subcircuit and the communication subcircuit operate independently of each other while sharing the common receive optocoupler. The circuit, as shown, only has two optocouplers while still providing timbre detection adjustability and an effective communication subcircuit that can be modified to meet the requirements of specific jurisdictions. This is particularly beneficial to cover the different requirements of different countries, while the components of the subcircuits can be varied without noticeably affecting the other subcircuits. The communication arrangement provides a convenient method for monitoring the condition of the telephone line and allows the microprocessor to effectively display the communication arrangement from time to time, and determine whether the telephone line is still present. Although various preferred embodiments of the present invention have been described in detail herein, those skilled in the art will appreciate that they may make various variations without departing from the scope of the appended claims.

Claims (5)

NOVELTY OF THE INVENTION CLAIMS

1. - A communications configuration (400) of a control panel (300) of a security alarm system, said communication configuration (400) selectively operates in a low current passive standby state or in a higher active state of current; said communication configuration (400) includes connection means for a telephone line (L1, L2) connecting said communication configuration (400) to a telephone line through which the telephone signals are received and transmitted; a microprocessor (420) for selecting the operating state of said communications configuration, receiving and transmitting signals on said telephone line, detecting call signs on said telephone line and evaluating the integrity of the telephone line; signal splitting means for dividing a received telephone signal for processing at a first branch of said communication circuit for the detection of the call signal and at a second branch for telephone line monitoring in said passive waiting state and for a complete communication in said active state; a switch configuration (402, 404) controlled by said microprocessor to exchange between a position, when said communication circuit is in said passive standby state, and a position where said communication circuit is in said mentioned active state; a receiving optocoupler (416) and a transmission optocoupler (418) through which said microprocessor (400) interacts with said telephone line; (• said first branch for the detection of call signal, in said passive waiting state of said switch, having circuitry for detection 5 call signal, which processes the signal of the telephone line blocking a CD component by passing the AC component of the call signal and producing an output signal and transmits said output signal to said receiving optocoupler when it has been detected a call signal in said CA component; said switch configuration, in said state of 10 passive waiting by connecting a large resistor (440, 442) in series with said second branch, whose large resistance significantly restricts the signal of said mentioned branch circuit to a very low output current for charging a charging device (430) to provide an indication of when the telephone line is operational, whose signal is not suitable for the 15 call signal detection; said charging device being operatively connected to said receiving optocoupler and said transmitting and discharging optocoupler when said microprocessor causes said receiving optocoupler to transmit a telephone line monitoring signal and said switch configuration is in said standby state 20 passive; said charging device (430) when unloading produces a signal that is received by said receiving optocoupler indicating that said telephone is working; said switch configuration (402, 404) in said active state causes said large resistance (440, 442) to deviate; a hook-off device (34) connected to said transmission optocoupler and controllable by said microprocessor (420) to cause said telephone line to be off-hook when the switch configuration (402, 404) is in said active state and said microprocessor (420 ) transmits an off-hook signal through said transmission optocoupler (418), said second branch being connected to said reception optocoupler (416) and providing AC communication signals in said active state, derived from said telephone signals; said microprocessor (420) monitoring said reception optocoupler (416) for a signal after initiating said telephone line monitoring signal to provide an evaluation as to whether said telephone is functioning; said first and second bifurcations operating independently between them, such that the components in a bifurcation can change without causing any substantial change in the operating characteristics of the other bifurcation.

2. The communication configuration according to claim 1, further characterized in that said bifurcation of said communication circuit extracts the CA component of the telephone signal and processes the CA component for a call signal.

3. The communication configuration according to claim 2, further characterized in that said bifurcation is essentially passive with a negligible output DC current to detect a call signal.

4. - The communication configuration according to claim 1, further characterized in that said communication configuration in said passive waiting state uses said telephone line to provide a slow current to charge said charging device (430) and uses said transmission optocoupler ( 418) and said receiving optocoupler (416) during the discharge of said charging device (430) to form a circuit with said charging device (430).

5. The communication configuration according to claim 1, further characterized in that said receiving optocoupler (416) acts as a normally open switch and closes selectively; said transmission optocoupler (418) when closed with said switch configuration in said passive standby state completes a circuit with said receiving optocoupler (416) and said charging device (430) allowing said charging device (430) to be download said transmission optocoupler (418) when closed with said switch configuration (402, 404) in said active state causing said off-hook device (34) to be off-hook with said receiving optocoupler (416) receiving signals over the telephone lines and said transmission optocoupler (418) transmits signals over said telephone lines.