A fixed telephone based remote alarm device

Abstract

The utility model discloses a kind of remote alarm device based on fixed telephone, it is related to remote alarm equipment field, for the instability problem existing in the dependence of existing alarm device on scene sound-light alarm and wireless communication alarm, the utility model includes circuit board box and battery box, the circuit board box is equipped with the circuit board of the core in this application, specifically including power module, control module, alarm module and voice module;Power module uses mains and battery double power supply system, mains power supply can charge battery simultaneously, mains interruption is automatically switched to battery power supply;Control module monitors power state, controls alarm module to carry out local warning and dial telephone alarm to specified number when mains interruption, voice module is played to specified number with voice alarm information;The utility model can monitor mains in real time, improve emergency response efficiency, suitable for unattended place power interruption alarm, with man-machine interaction and maintenance convenience.

Description

Technical Field

[0001] This utility model relates to the field of remote alarm equipment, and in particular to a remote alarm device based on a landline telephone. Background Technology

[0002] With the construction and improvement of information and communication engineering, various industries have established relatively complete information security systems. As an important link in information and communication security, the operation of unmanned data centers and unmanned stations has become a crucial part of this process. Although these data centers and facilities are equipped with UPS power supplies during construction to provide power during power outages, the inconsistencies between manufacturers of transmission equipment and UPS power supplies on the market, as well as incompatible communication protocols, can lead to situations where mains power is interrupted, UPS power is depleted, and power supply to facilities is interrupted without timely alarms, thus affecting the normal operation of transmission equipment.

[0003] Traditional alarm devices often rely on speakers or on-site displays to issue audible and visual alarms. This method not only requires significant human monitoring but is also susceptible to environmental interference. Some remote alarm systems on the market utilize modern wireless communication networks, allowing users to communicate with the system via mobile phones or mobile apps. This technology is widely used in smart homes and home security, but its reliance on base stations, weak anti-interference capabilities, and vulnerability to intrusion make it unsuitable for remote, underground, uninhabited, or other critical locations requiring 24 / 7 continuous operation. Therefore, developing a remote alarm device capable of real-time monitoring of mains power and environmental conditions, automatically triggering an alarm upon detecting anomalies, and promptly transmitting alarm information to the control room or monitoring center via reliable communication is crucial.

[0004] Patent application CN100583933C discloses a remote telephone control and alarm device for use with a home gateway to achieve smart home appliance control and system security alarms. The device includes a data access management chip MH88435, a microcontroller, a DTMF (Dual-Tone Multi-Frequency) transceiver chip, a voice chip, and a power supply. The data access management chip detects ringing and automatically picks up and hangs up. The microcontroller controls ringing count, pick-up and hang-up, and the DTMF transceiver chip and voice chip. Using a built-in EEPROM, the device stores and modifies passwords and outgoing dial numbers. After verifying the password and confirming the user's identity, it receives user key presses and sends them to the gateway via a serial port to control home appliances and query their status. When the gateway sends an alarm signal, the microcontroller reads the corresponding outgoing dial number from the EEPROM, automatically dials, and after a delay, plays an alarm prompt voice. After hanging up, the microcontroller automatically enters sleep mode. The device features low power consumption, good security, high reliability, and small size.

[0005] However, the remote control and alarm device still has the following problems when in use: (1) The remote control and alarm device is powered by a single 5V DC power supply and lacks a redundant power supply design or backup energy storage unit to cope with power outages, which cannot meet the requirements of power supply continuity in critical security scenarios. (2) The remote control and alarm device only uses a voice chip to transmit pre-stored alarm prompt voice to the remote end, and is not equipped with an audio-visual alarm unit. On-site personnel may not be able to perceive the alarm status in time. (3) The remote control and alarm device lacks an audio monitoring loop, making it impossible to verify the quality of call content transmission and the accuracy of alarm information in real time. Utility Model Content

[0006] To address the aforementioned problems, this utility model aims to provide a remote alarm device based on a landline telephone. It employs a dual power supply system of mains power and battery to ensure continuous operation and real-time monitoring of power supply status. Through a dual alarm mechanism of buzzer and telephone voice, it significantly improves emergency response efficiency. An integrated microphone enables on-site audio pickup, and an earphone jack supports real-time call monitoring, enhancing interactivity. It utilizes an externally mounted TM1638 display module that supports intermittent connection, allowing for dynamic adjustment of the preset local number and call number during operation, thus improving system maintenance convenience. It is suitable for power outage alarm needs in important locations such as unattended facilities.

[0007] To achieve the above objectives, the technical solution adopted by this utility model is as follows: A remote alarm device based on a landline telephone includes: a circuit board box and a battery box, wherein the battery box contains a battery, and further includes: The circuit board, housed inside the circuit board box and connected to the battery, is used to monitor the mains power status, issue local warnings and make phone calls to designated numbers when the mains power is interrupted, and play voice alarm information through a landline after the call is connected.

[0008] The circuit board includes: The power module consists of two parts: mains power supply and battery power supply. The mains power supply is used to power the device and charge the battery. When the mains power is normal, the battery does not supply power. When the mains power is interrupted, the battery supplies power to the device. A control module, connected to the power supply module, is used to monitor the power supply status and control the activation of the alarm program; An alarm module, connected to the control module, is used for local alerts and making telephone alarms to designated numbers. The voice module is connected to the control module. After the alarm module connects to a designated number, the control module sends a command to the voice module to play the designated voice alarm information.

[0009] The control module includes: A microprocessor, integrated into the control module, is used to perform logic processing for power supply status monitoring and alarm programs; The program burning module is connected to the microprocessor and is used to write the corresponding program into the microprocessor's memory chip; A button module, connected to the microprocessor, is used as an auxiliary button for debugging and controlling the program; An LED feedback module is connected to the microprocessor and is used to provide feedback on the current operating status of the microprocessor.

[0010] Furthermore, the circuit board also includes: The parameter configuration module is detachably connected to the control module and is used to change the preset local number and call number during the operation of the device.

[0011] Furthermore, the alarm module includes: A local alarm module, connected to the microprocessor, is used to detect local alerts after a power outage. The telephone alarm module is connected to the microprocessor and is used to make a phone call to a designated number after the microprocessor issues a control command.

[0012] Furthermore, the telephone alarm module includes: A DTMF signal transceiver circuit, connected to the microprocessor, is used to transmit and receive DTMF signals and identify the call status of fixed telephone lines after the microprocessor issues control commands. A signal processing circuit, connected to the DTMF signal transceiver circuit and the voice module, is used to process input and output signals on the fixed telephone line; A ring detection module, connected to the microprocessor and the signal processing circuit, is a redundant circuit used by the microprocessor to identify the call status of a fixed telephone line; A telephone line interface is connected to the signal processing circuit for connecting to a landline telephone line.

[0013] Furthermore, the voice module includes: A voice playback module is connected to the microprocessor and controls the playback of voice files through the microprocessor's serial port; A voice amplification circuit, connected to the signal processing circuit, amplifies the local recording signal and then connects it to a fixed telephone line. The telephone monitoring module is connected to the voice amplification circuit and is used to monitor the voice signal in the line.

[0014] The beneficial effects of this utility model are: (1) This utility model adopts a dual power supply system of mains power and battery. When both mains power and battery are powered normally, the battery will not supply power due to the action of the field effect transistor, and the mains power will supply power. At the same time, the mains power charges the battery through the field effect transistor. When the mains power is interrupted, it will automatically switch to battery power supply to ensure that the device can still work normally when the mains power is interrupted, avoid monitoring interruption caused by power outage, and improve the reliability and continuity of the system. (2) This utility model adopts two methods: buzzer alarm and telephone voice alarm. The buzzer alarm provides immediate local warning, while the telephone alarm transmits the pre-stored alarm prompt voice to the telephone line through the voice playback module composed of JR6001 voice chip and FLASH flash memory. The voice file supports software synthesis and manual recording. The alarm content can be dynamically configured according to the security level, which significantly improves the system adaptability. The integrated microphone can realize on-site sound recording, and the standard 3.5mm headphone jack can realize real-time monitoring of the call content, ensuring the accuracy and effectiveness of alarm information transmission. (3) This utility model uses an external TM1638 display module to realize the operation of changing the preset local number and call number during the operation of the device. During normal operation, it does not need to be connected to the control module at all times, which reduces the average hardware cost of a single system. By integrating key scanning and LED display module to modify the program, combined with the EEPROM function built into the microprocessor, it replaces the traditional firmware burning method, which improves the maintainability and intuitiveness of the system. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of a remote alarm device based on a landline telephone, as proposed in this utility model.

[0016] Figure 2 This is a schematic diagram of the circuit board proposed in this utility model.

[0017] Figure 3 The circuit diagram of the power module proposed in this utility model is shown.

[0018] Figure 4 This is the circuit diagram of the microprocessor proposed in this utility model.

[0019] Figure 5 The circuit diagram of the button module proposed in this utility model is shown.

[0020] Figure 6 This is the circuit diagram of the LED feedback module proposed in this utility model.

[0021] Figure 7 The circuit diagram of the programming module proposed in this utility model is shown.

[0022] Figure 8 This is the circuit diagram of the local alarm module proposed in this utility model.

[0023] Figure 9 This is a circuit diagram of the DTMF signal transceiver proposed in this utility model.

[0024] Figure 10 This is the circuit diagram of the ringing detection module proposed in this utility model.

[0025] Figure 11 This is the signal processing circuit diagram proposed in this utility model.

[0026] Figure 12 This is a circuit diagram of the telephone line interface proposed in this utility model.

[0027] Figure 13 This is the interface circuit diagram of the voice playback module proposed in this utility model.

[0028] Figure 14 The diagram shows the voice amplifier circuit proposed in this utility model.

[0029] Figure 15 This is a circuit diagram of the telephone monitoring module proposed in this utility model.

[0030] Figure 16 This is the interface circuit diagram of the parameter configuration module proposed in this utility model.

[0031] The above figures include the following reference numerals: 1. Circuit board box; 2. Battery box; 3. Battery; 4. Circuit board. Detailed Implementation

[0032] To enable those skilled in the art to better understand the technical solution of this utility model, the technical solution of this utility model will be further described below with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are only a part of the embodiments, and not all of the embodiments.

[0033] Example 1: As attached Figure 1 and attached Figure 16 As shown, this application discloses a remote alarm device based on a landline telephone, including: a circuit board box 1 and a battery box 2. The battery box 2 contains a battery 3, and the circuit board box 1 contains a circuit board 4. The circuit board 4 is connected to the battery 3. The circuit board 4 is used to monitor the mains power status, provide local warnings and make phone calls to designated numbers when the mains power is cut off, and play voice alarm information through the landline telephone line after the call is connected.

[0034] Specifically, the schematic diagram of the circuit board 4 is shown in the attached figure. Figure 2 As shown, it includes: a power module, a control module, an alarm module, and a voice module.

[0035] The power module consists of two parts: mains power supply and battery 3 power supply. The mains power supply uses a power adapter to convert 220V mains power into 5V DC power. The battery 3 power supply uses a 2400mAh lithium battery. When both mains power and battery 3 are supplying power normally, the current in the battery 3 power supply line is blocked due to the action of the field-effect transistor, so battery 3 does not supply power, while mains power supplies power normally. At the same time, mains power charges battery 3 through the field-effect transistor. When the mains power is interrupted, the field-effect transistor turns off. At this time, the current in the battery 3 power supply line flows into the device through the Zener diode, that is, the battery 3 automatically switches to supply power to the device, thereby realizing that the power module continuously supplies power to the device. The overall power of the device does not exceed 10W. The control module is connected to the mains power and the battery 3 power supply lines through two IO interfaces respectively. The high and low levels of the IO interfaces are used to determine whether the power supply status of the mains power and the battery 3 is normal. If the IO interface connected to the mains power shows a low level, it indicates that the mains power is disconnected. At this time, the control module immediately starts the alarm program. The control module also reserves IO interfaces as expansion function interfaces, which can be connected to various environmental detection sensors in the future. The alarm module is connected to the control module and is used to issue a local alert while simultaneously dialing a designated number to trigger an alarm. The voice module is connected to the control module through the IO interface on the circuit board 4. After the alarm module connects to the designated number, the control module sends a command to the voice module to play the designated voice alarm information and transmit it to the telephone line. The designated telephone in the duty room or monitoring center can receive the alarm information in time when the mains power is interrupted.

[0036] Furthermore, the control module includes a microprocessor, a program programming module, a button module, and an LED feedback module.

[0037] Specifically, the microprocessor uses the STC15F2K60S2 series microcontroller, which features high speed, low power consumption, and strong anti-interference capabilities. It has a built-in 2K-byte large-capacity SRAM and a large-capacity on-chip EEPROM, eliminating the need for an external crystal oscillator and reset circuit. It monitors the power supply status of the mains and battery 3 in real time through two I / O interfaces. Under normal mains power supply, the I / O interface connected to the mains is at a high level. When the mains power is interrupted, the I / O interface connected to the mains switches to a low level. At this time, the microcontroller immediately starts the alarm program and performs an outbound call alarm through the alarm module. During the dialing process, the signal tone on the fixed telephone line is detected. If the signal is a square wave, it indicates that a valid signal tone has been received. The on / off time of the square wave is then detected to determine whether the call was successful (the dial tone is a continuous 450Hz signal; the busy tone is 0.35 seconds on, 0.35 seconds off; the ringback tone is 1 second on, 4 seconds off). After a successful call is detected, the voice module is controlled via the serial port to output a voice file. When the voice is played, the microcontroller receives a high-level response from the voice module. The programming module is connected to the microprocessor via a set of serial ports to write the corresponding program into the microprocessor's memory chip. The programming module is also equipped with a filtering component and a single-pole double-throw switch. The filtering component consists of three parallel filtering capacitors. When the switch is to the power supply side of the power module, the 5V DC power output by the power module supplies power to the microprocessor through the three filtering capacitors. When the switch is to the pin header side, an external power supply is introduced through the pin header pins for the microprocessor's encoding and debugging operations. At this time, the external power supply supplies power to the microprocessor through the three filtering capacitors. The button module includes three tactile button switches, which are connected to the I / O interface of the microprocessor and used as auxiliary buttons for debugging and controlling the program; The LED feedback module uses a set of LED indicators connected to the microprocessor's I / O interface. Driven by a low level, it provides feedback on the current operating status of the microprocessor.

[0038] Furthermore, the circuit board 4 also supports a parameter configuration module. The parameter configuration module adopts an externally mountable TM1638 display module, including 8 buttons, 8 LED indicators, and an 8-digit digital tube. It is connected to the control module through the IO interface on the circuit board 4 and is used to change the preset local number and call number during the operation of the device. The parameter configuration module does not need to maintain a constant connection with the control module during operation. When it is necessary to change the preset local number or call number, the modification program can be entered through the button module, and then the preset parameters can be displayed and modified through the parameter configuration module.

[0039] Furthermore, the alarm module includes a local alarm module and a telephone alarm module. The local alarm module uses a transistor to drive a buzzer to emit a loud sound to warn nearby personnel. The buzzer frequency is selected as 3KHz. The transistor is connected to the I / O interface of the microprocessor. The buzzer is driven at a low level to provide a local warning after detecting a power outage. The telephone alarm module is connected to a set of I / O interfaces of the microprocessor and is used to dial a designated number after the microprocessor issues a control command.

[0040] Furthermore, the telephone alarm module includes a DTMF signal transceiver circuit, a signal processing circuit, a ring detection module, and a telephone line interface.

[0041] Specifically, the DTMF signal transceiver consists of the MT8880 chip and its auxiliary components. The MT8880 is a dual-tone multi-frequency (DTMF) codec chip that integrates DTMF signal transmission and reception. The data bus D0~D3 is connected to the microprocessor's I / O interface for bidirectional data transmission. The read / write control pin R / W is connected to the microprocessor's I / O interface to determine the data direction. The register select pin RS0 is connected to the microprocessor's I / O interface to select the MT8880 chip's internal registers. The interrupt request / call processing mode select pin IRQ / CP is connected to the microprocessor's external interrupt interface to select the MT8880 chip's operating mode. The MT8880 chip has DTMF signal input and output terminals for processing DTMF signals after the microprocessor issues control commands. The microprocessor can simultaneously set the MT8880 chip's operating mode to call processing mode and interrupt request mode via the IRQ / CP interface. Then, it sends the outgoing phone number stored in the built-in EEPROM to the MT8880 chip via the data bus D0~D3. During dialing, if a valid tone is received, the IRQ / CP pin outputs a square wave; otherwise, the IRQ / CP pin is low. By detecting the signal at the IRQ / CP interface, it can be determined whether the call was successful. It should be noted that the control module allows the MT8880 chip to operate simultaneously in call processing mode and interrupt request mode. Therefore, when a call comes in on a landline, the microprocessor reads the square wave through the IRQ / CP interface and counts the changes in the square wave's high and low levels to determine whether the call was successful.

[0042] The signal processing circuit is connected to the DTMF signal input and DTMF signal output terminals of the MT8880 chip, and is also connected to the voice output terminal of the voice module. It is used to rectify, filter, adjust the level, and isolate and protect the input and output signals on the fixed telephone line. The ring detection module rectifies the dual-tone signal from the signal processing circuit into high and low levels after optocoupler isolation and inputs it to the microprocessor, so that the microprocessor can analyze the signal tone type and determine the call status. At the same time, the microprocessor identifies the call status of the landline through the call processing and interrupt request mode of the MT8880 chip. The software identification paths of the ring detection module and the microprocessor are redundant and work together to detect the call status of the landline.

[0043] The telephone alarm module has two telephone line interfaces for connecting to a landline. The two telephone line interfaces are redundant and each is connected to a landline phone. The backup landline phone can be used normally when not in use, and can also be used as a monitoring line when the device is running.

[0044] Furthermore, the voice module includes a voice playback module, a voice amplification circuit, and a telephone monitoring module.

[0045] Specifically, the voice playback module adopts the JR6001 voice playback module, which consists of a JR6001 voice chip and FLASH flash memory. The voice files support software synthesis and manual recording. The voice file playback is controlled by the serial port of the microprocessor. It has a voice output terminal. When playing voice, the BUSY pin of the JR6001 voice playback module outputs a high level, and the AD_KEY pin is grounded through a button switch. The playback, pause and switching functions of the voice file can be realized through physical buttons. The voice amplification circuit uses a condenser microphone to pick up audio on-site, amplifies the local recording signal, and then connects it to a fixed telephone line. The telephone monitoring module has a landline handset cable socket interface and a standard 3.5mm headphone jack for monitoring voice signals in the line. The landline handset cable socket is connected to the microphone output end and the voice output end of the voice module. After dialing a call, the handset can directly hear the content of the call, or it can insert the headphone into the headphone jack to monitor the voice content in the line by wearing the headphone.

[0046] Furthermore, the circuit diagrams of each component in the device described in this utility model are attached. Figure 3-16 As shown, where, Figure 3 This is the circuit diagram for the power module. Figure 4 This is a microprocessor circuit diagram. Figure 5 This is the circuit diagram for the button module. Figure 6 This is the circuit diagram for the LED feedback module. Figure 7 The circuit diagram for the program burning module, Figure 8 This is the circuit diagram for the local alarm module. Figure 9 This is a circuit diagram for DTMF signal transceiver. Figure 10 This is the circuit diagram for the ring detection module. Figure 11This is a signal processing circuit diagram. Figure 12 This is a circuit diagram for a telephone line interface. Figure 13 This is the interface circuit diagram for the voice playback module. Figure 14 This is a diagram of a voice amplifier circuit. Figure 15 This is the circuit diagram for a telephone monitoring module. Figure 16 Parameter configuration module interface circuit diagram.

[0047] The working principle of this utility model is as follows: Step 1: Connect the mains power supply to the device via the power adapter, switch the single-pole double-throw switch to the power supply terminal of the power module, and supply power to the microprocessor through the 5V DC output of the power module. Press the corresponding button switch of the button module to put the microprocessor into normal working state. At this time, the LED indicator of the LED feedback module flashes to indicate that the microprocessor is monitoring. Step 2: When the mains power is interrupted, the I / O interface of the microprocessor connected to the mains power jumps to a low level. The microprocessor detects the mains power interruption signal, immediately starts the alarm program, controls the I / O interface connected to the transistor to output a low level, and drives the buzzer to emit a loud sound to warn nearby people. Step 3: Simultaneously, the microprocessor sets the MT8880 chip's operating mode to both call processing mode and interrupt request mode via the I / O interface, and transmits the outgoing phone number stored in the built-in EEPROM via the I / O interface, while detecting the ringing tone during the dialing process. Step 4: After the microprocessor detects a successful dialing, it controls the voice module via the serial port to play the pre-stored voice file. Once the recipient answers the call, they can perform corresponding operations based on the voice information. For example, when the recipient presses the "1" key, the microprocessor receives a request to query its own information and sends its own number to the recipient's phone. When the recipient presses the "#" key, the microprocessor receives a request to hang up the call and controls the telephone line to disconnect, completing the remote telephone communication interaction. This is similar to the IVR (Interactive Voice Response) self-service voice service used in telecommunications and mobile phones. This content is not within the specific scope of this application and is only provided as an example. Specific implementation can be achieved through corresponding program settings according to actual needs. Step 5: During device operation, if it is necessary to modify the preset local number or call number, the parameter configuration module can be connected to the corresponding IO interface on circuit board 4, the modification program can be entered through the button module, and then the preset parameters can be displayed and modified through the parameter configuration module; Step Six: When relevant personnel need to inspect the device or make remote calls through the device, they can use the microphone to record audio on-site, and wear headphones to listen to the audio content on the line at the same time.

[0048] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A remote alarm device based on a landline telephone, comprising: The circuit board box (1) and the battery box (2), wherein the battery box (2) contains a battery (3), characterized in that it further includes: The circuit board (4) is set inside the circuit board box (1) and connected to the battery (3) for monitoring the mains power status, issuing local warnings and making phone calls to designated numbers when the mains power is interrupted, and playing voice alarm information through a fixed telephone line after the call is connected; The circuit board (4) includes: The power module consists of two parts: mains power supply and battery (3) power supply. The mains power supply is used to power the device and charge the battery (3). When the mains power is normal, the battery (3) does not supply power. When the mains power is interrupted, the battery (3) supplies power to the device. A control module, connected to the power supply module, is used to monitor the power supply status and control the activation of the alarm program; An alarm module, connected to the control module, is used for local alerts and making telephone alarms to designated numbers. A voice module is connected to the control module. After the alarm module connects to a designated number, the control module sends a command to the voice module to play the designated voice alarm information. The control module includes: A microprocessor, integrated into the control module, is used to perform logic processing for power supply status monitoring and alarm programs; The program burning module is connected to the microprocessor and is used to write the corresponding program into the microprocessor's memory chip; A button module, connected to the microprocessor, is used as an auxiliary button for debugging and controlling the program; An LED feedback module is connected to the microprocessor and is used to provide feedback on the current operating status of the microprocessor.

2. The remote alarm device based on a landline telephone according to claim 1, characterized in that, The circuit board (4) also includes: The parameter configuration module is detachably connected to the control module and is used to change the preset local number and call number during the operation of the device.

3. The remote alarm device based on a landline telephone according to claim 1, characterized in that, The alarm module includes: A local alarm module, connected to the microprocessor, is used to detect local alerts after a power outage. The telephone alarm module is connected to the microprocessor and is used to make a phone call to a designated number after the microprocessor issues a control command.

4. A remote alarm device based on a landline telephone according to claim 3, characterized in that, The telephone alarm module includes: A DTMF signal transceiver circuit, connected to the microprocessor, is used to transmit and receive DTMF signals and identify the call status of fixed telephone lines after the microprocessor issues control commands. A signal processing circuit, connected to the DTMF signal transceiver circuit and the voice module, is used to process input and output signals on the fixed telephone line; A ring detection module, connected to the microprocessor and the signal processing circuit, is a redundant circuit used by the microprocessor to identify the call status of a fixed telephone line; A telephone line interface is connected to the signal processing circuit for connecting to a landline telephone line.

5. A remote alarm device based on a landline telephone according to claim 4, characterized in that, The voice module includes: A voice playback module is connected to the microprocessor and controls the playback of voice files through the microprocessor's serial port; A voice amplification circuit, connected to the signal processing circuit, amplifies the local recording signal and then connects it to a fixed telephone line. The telephone monitoring module is connected to the voice amplification circuit and is used to monitor the voice signal in the line.

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