KR950000530B1 - Ring detection method utilizing a microprocessor - Google Patents

Abstract

In the telephone terminal using microprocessor, the ring signal detecting method from PSTN not using ring detecting IC employs an RF module (12) that sends and receives RF signal, a modem (14), a memory (EEPROM) (16) that saves ID code, a CPU (18) that controls peripheral units and processes the program, a communication circuit (20) that receives and sends the voice signal, and a wave shaper (24).

Description

Ring Detection Method Using Microprocessor

1 is a hardware block diagram of a conventional wireless telephone,

2 is a circuit diagram of a radiotelephone according to the present invention;

3 is a waveform normalization diagram of a ring signal for explaining the operation of FIG.

4 is a ring interrupt flowchart according to the present invention;

5 is a timer control flowchart according to the present invention;

6 is a ring check control flow chart according to the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting a ring signal from a telephone network, and more particularly, to a system comprising a device connected to a telephone network (hereinafter referred to as a fixed device) and a device for making or receiving a call while the user carries it. The present invention relates to a ring detection method for effectively detecting a ring signal transmitted from a telephone network by distinguishing it from other signals.

Typically, the majority of wired and wireless terminals, especially telephone terminals connected to the telephone line of the telephone network (PSTN) are to be made in response to the ring signal from the telephone network. For the above operation, all wired telephone terminals are provided with a circuit for detecting a ring signal from the telephone network.

The conventional radiotelephone fixing device is connected to a telephone network to detect a ring from the telephone network, and when the ring is detected, establishes a call channel with a portable device.

1 is a block diagram of a fixing device of a conventional radiotelephone, wherein the fixing device converts an analog signal input into a digital signal and converts an analog signal input into a digital signal including an RF module 12 including a transmitting and receiving device for receiving signals (voice and data). Modem and logic circuits (hereinafter referred to as "modems") 14 for converting signals into analog signals, memory (EEPROM) 16 that stores ID numbers of fixed devices, and various states to users. A speaker 23 capable of informing the user, and a central processing unit 18 for controlling the peripheral device by a built-in program and performing a processing process, and a call circuit for transmitting and receiving a voice signal with a telephone network (PSTN). IC) 20 and a ring detector 22 for detecting a ring from the telephone network PSTN.

The ring detection unit 22 in the configuration of FIG. 1 is a ring detection dedicated circuit for detecting a ring signal by inputting a signal from the outside.

If a ring is now transmitted from the public network to the circuit of FIG. 1, it is input to the ring detector 22. At this time, the ring detector 22 detects the input ring signal and sets a ring detection pin to set the ring detection terminal to input the signal indicating that the ring is detected to the CPU 18. At this time, the CPU 18 checks the detection signal at predetermined intervals and knows that there is a ring signal.

Therefore, it can be seen that a conventional circuit such as the first diagram detects a ring as a ring detection dedicated integrated circuit.

However, the circuit using the ring detection dedicated integrated circuit as described above has the following problems.

For example, when a noise signal of a predetermined magnitude or more is applied to the telephone line and input to the ring detector 22, the ring detector 22 misdetects the signal as a ring signal and generates a ring detection signal.

The central processing unit 18 recognizes the ring detection signal as a ring, and prevents it as various high-speed (H / S) elements from the outside, which also causes the telephone line to age. When a noise signal in the form of a pulse is applied to the signal line, the ring cannot be detected efficiently.

Accordingly, an object of the present invention is to provide a method for efficiently detecting a ring signal from a telephone network without using a ring detection integrated circuit in a telephone terminal using a microprocessor.

Another object of the present invention is to provide a method for detecting a ring signal by checking a duration of a specific level of a signal input from a telephone network.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

2 is a circuit diagram of a fixing device for a radiotelephone according to the present invention, and an RF signal (12) for transmitting and receiving RF signals (voice and data) through an antenna and an analog signal connected to the RF module (12). The modem 14 converts the input into a digital signal and converts the digital signal into an analog signal, a memory (EEPROM) 16 storing a fixed number (ID COED) of a fixed device, and a built-in program. A central processing unit (hereinafter referred to as CPU) 18 for controlling peripheral devices and performing processing processes, a communication circuit 20 connected to a telephone network PSTN to transmit and receive voice signals, and a connection to the telephone network PSTN. And a waveform shaping unit 24 for waveform shaping a signal of a predetermined level or more and outputting the same to the CPU 18.

The waveform shaping section 24 is composed of a capacitor 26, resistors 28, 32, 38, a light emitting diode 34, and a photo transistor 26.

3 is an operational waveform diagram of a portion of FIG. 2, where (3a) is a waveform diagram of a ring signal, (3b) is a level limited ring signal waveform, and (3c) is a waveform diagram of a waveform-shaped ring signal.

4 is a ring interrupt flow chart according to the present invention, which drives a timer that checks a ring frequency check flag (RFCF) and detects a duration of a currently input ring signal in response to an interrupt by an input of a ring signal, Storing a value stored in a TRC (Temp Ring Counter) to calculate a frequency of the input signal in a ring counter (RC), and storing a value of a minimum frequency in the TRC, The detailed flow has the following procedure.

An input signal state search process for searching whether the current input signal is a signal due to a falling edge in response to an interrupt caused by a ring signal input, and a signal rising when a signal is detected by a falling edge in the signal state search process. An RC initialization process for resetting an edge detection flag and loading TRC values into RC, a rising edge detection request bit, and a TRC initialization process for loading a minimum frequency value for detecting a ring into the TRC; And setting a rising edge detection flag and setting a first level (eg, high section) section detection timer of the input signal and disabling a ring interrupt when determining that the signal is a rising edge signal in the signal state search process. Consists of

5 is a flowchart of a timer control according to the present invention, which is operated at a predetermined period to decrease the maximum frequency value loaded in the TRC, and enables the ring interrupt when the first level interval detection timer times out. The procedure is sensed as follows.

Decreases the value of TRC by a predetermined period by "1", and detects whether the "high" section detection timer has expired when the rising edge detection flag is set, and determines that the timer has ended in the timer search process. Enable ring interrupt at the time of detection, and set the high edge detection request bit at the time when the ring detection port is "high" during the ring signal input search process to search whether the ring detection mode is "high" And resetting the rising edge detection flag at the same time, and immediately resetting the rising edge detection flag when the detection port is "low".

6 is a ring inspection flow chart according to the present invention, which includes a ring detection state searching process for searching whether a ring has already been detected, a value stored in RC and a preset minimum frequency value when it is determined that no ring is already detected in the search process. A ring frequency first search process for searching a ring frequency by comparison, a call connection process for executing a call connection when the RC value is greater than a predetermined minimum frequency value as a result of the search of the ring frequency first search process, and in the search process A second ring frequency search process for searching for a ring frequency by comparing a value stored in RC with a preset minimum frequency value when it is determined that a ring is already detected; and a minimum frequency in which the RC value is preset as a result of the search for the ring frequency second search Counting Ring Ecd Counter (REC) when determined to be less than the value and determining that the RC value is greater than the minimum frequency value And a ring input state searching process for searching whether the REC is terminated, and stopping a ring sound when the ring input search home determines that the REC is not finished, and stopping a call connection when the REC ends.

Hereinafter, an example of the operation of the present invention will be described in detail.

When a ring signal as shown in FIG. 3A is input from the telephone network PSTN, the ring signal is made as shown in FIG. 3B by the capacitor 26 resistor 28 and the zener diode 30. Accordingly, a signal as shown in FIG. 3B appears between both ends A and B of the light emitting diode 34. At this time, the light emitting diode 34 emits light during the “high” period (+ period) of FIG. 3B, so that the waveform at the output point E of the phototransistor 36 is displayed as shown in FIG. 3C. The signal as shown in FIG. 3C is input to the interrupt terminal INT and the ring detection port ROT of the CPU 18.

At this time, the CPU 18 interrupt is generated, and by the interrupt generation, the CPU 18 detects the signal input of the ring detection port ROF and checks the frequency of the signal, and determines whether the frequency is a ring signal. It is determined by the following procedure.

First, when the interrupt is detected, the CPU 18 checks whether the currently detected interrupt is a falling edge or a rising edge (step 41). If the interrupt is detected at the falling edge, the CPU 18 indicates that a rising edge has been detected. The flag is reset (step 42), and the contents stored in the TRC (temp-ring-counter) calculated so far are transferred to the ring counter RC ("ring counter") set in the RAM (step 43).

The CPU 18 then sets a rising edge detection request bit (step 44) and sets a counter value corresponding to the minimum frequency of the ring signal to a temp-ring-counter (TRC). Save to the area of (45). At this time, the value stored in the TRC (temp-ring-counter) decreases every predetermined time (the smaller the value stored in the TRC, the larger the frequency resolution is).

If the rising edge is detected in step 41, the CPU 18 resets the rising edge detection flag indicating that the rising edge is detected (step 46), and then the A timer is set to check the duration of the high state (step 47) and the ring interrupt is disabled (step 48).

On the other hand, the CPU 18 having set the minimum value for detecting the ring in the TRC by the operation of FIG. 4 performs the operation of FIG. 5 every 2 Msec to adjust the value of the TRC, and sets the high section of the ring signal. The search is as follows.

FIG. 5 is a routine performed every predetermined time (2 msec) to decrease the value of the temporary ring frequency counter TRC (temp ring counter) by 1 (step 51) and to check whether the rising edge detection flag is set (step 51). Course 52).

If a falling edge is detected as a result of the search in step 52, the CPU 28 terminates the routine of FIG.

If the rising edge is detected, the CPU 18 checks whether or not the 4 msec timer has expired (step 53). If not, the CPU 18 terminates this routine, and if the 4 msec timer expires, the CPU 18 Enables the ring interrupt (step 54) and checks the input of the ring signal input port (ROT) to see if the ring signal remains high (step 55).

If the input of the search result input port ROT of step 55 is still high, the CPU 18 considers it as a part of a normal signal waveform and sets a falling edge request detection flag (step 56), and detects a rising edge. Reset the flag (step 57). If the ring signal is already low in step 55, the CPU 18 determines that a normal high signal has not yet been detected, and immediately resets the rising edge detection flag in step 57 and terminates this routine.

Then, the CPU 18 checks whether a ring has been detected (step 61) in FIG. 6 and checks whether a ring frequency check flag (RFCF) is set if the ring has already been detected. (62 courses). If RFCF is not set in step 62, the CPU 18 checks whether the value stored in the TRC (temporary ring counter) is greater than 20 (step 63). If the value is greater than 20, the value of the temp-ring-counter (TRC) is increased. Is set to the roll FF (step 65). If the TRC value is less than 20 in step 63, the CPU 18 is currently monitoring the ring frequency and thus simply terminates this process.

If RFCF, which is a ring frequency check flag, is set in step 62, it is checked whether the value of the ring counter RC is smaller than a value corresponding to the highest frequency (step 66), and if it is small, a ring-detect flag (flag-Detect-ring). ) Is set, or the ring detection flag is reset. Thereafter, if the ring detection flag is set, it is checked whether one ring has already been detected, and if it is already detected, it is determined that there is a ring signal from the telephone network. If it is determined that the first ring signal is set, a flag first ring indicating that the first ring is detected is set and the process is completed.

If it is determined that there is a ring signal from the telephone network, a ring tone is generated through the speaker to inform the user that there is a call from the telephone network, and at the same time, the user attempts to connect a call to a mobile device by searching for an empty channel according to a predetermined method (step 68). .

If the ring signal is already detected in step 61, the CPU 18 checks again whether a flag-check-ring-freq (RFCF), which is a ring check flag, is set (68). Check if the ring stop watchdog timer (time-ring-End) has been reduced to " 0 " (step 72). If the ring-stop monitoring timer (time-ring-Ecd) becomes "0" in the search process, the CPU 18 determines that the ring is already stopped and forcibly terminates the call connection process to the mobile device currently in progress ( 73 courses).

On the other hand, if a flag-check-ring-freq (RFCF) is set in step 68, the CPU 18 checks the ring frequency by reading the value of TRC in step 68, and the value of RC is the minimum in step 70. Check for less than frequency.

In step 70, if the value stored in the temporary ring counter TRC (temp-ring-counter) is smaller than the counter value corresponding to the smallest ring frequency, it may be determined that the current ring frequency is being counted. If the ring stop watchdog timer (timer-ring-End) is reduced to " 0 ", the call connection process to the attempted portable device is also forcibly terminated (step 73).

If the ring stop watch timer (timer-ring-End) is not yet reduced to "0" in step 72, it is determined that the ring is not yet reached a certain time since the ring was detected. Notify this to the portable device.

In addition, the ring-ring-ON flag is reset, and the current state indicates that the ring is not detected and ends.

As described above, the present invention can selectively detect the ring signal by accurately distinguishing the ring signal transmitted to the telephone network from other signals using the CPU, thereby preventing malfunction of ring detection due to noise.

Claims (3)

An RF module 12 which transmits and receives an RF signal through an antenna, and a modem 14 connected to the RF module 12 to convert an analog signal input into a digital signal and convert the digital signal into an analog signal; In addition, the memory 16 stores the ID number of the fixed device (ID COED), the central processing unit (18) for controlling the peripheral device by the built-in program and performs a process, and the telephone network (PSTN) A ring having a call circuit 20 connected and transmitting and receiving a voice signal, and a waveform shaping unit 24 connected to the telephone network PSTN and waveform-shaping a signal of a predetermined level or more and outputting the signal to the CPU 18. A detection method comprising: driving a timer for checking a duration of a ring signal currently input while checking an RFCF in response to an interrupt by an input of a ring signal through the telephone network (PSTN), and calculating a frequency of the input signal TRC for A signal input detection process of storing the stored value in RC, and storing the value of the minimum frequency in the TRC, and reducing the maximum frequency value loaded in the TRC by operating a predetermined period, and the first level interval detection timer is timed out. A signal detection process for enabling the ring interrupt at the end), a ring detection state search process for searching whether a ring has already been detected, and a value stored in RC and a preset minimum value when it is determined that no ring has already been detected in the search process. A ring frequency first search process for searching a ring frequency compared to a frequency value, a call connection process for executing a call connection when the RC value is greater than a predetermined minimum frequency value as a result of the search in the ring frequency first search process; Ring note that searches for ring frequency by comparing the value stored in RC with the preset minimum frequency value when it is determined that the ring has already been detected in the search process The ring termination counter REC is counted when it is determined that the RC value is smaller than a preset minimum frequency value as a result of the second search process and the search of the ring frequency second search, and determines that the RC value is larger than the minimum frequency value. And a ring input state searching process for searching whether the REC is terminated when the REC is terminated, and stopping ringing when the REC is not finished in the ring input searching process, and stopping the call connection when the REC terminates. The signal input detection process of claim 1, wherein the signal input detection process comprises: an input signal state search process for searching whether a current input signal is a signal due to a falling edge in response to an interrupt by an input of a ring signal, and a falling edge during the signal state search process; The RC initializing process of resetting the rising edge detection flag and loading TRC value into RC when the signal is determined by the signal, setting the rising edge detection request bit, and setting the minimum frequency value to detect the ring. A TRC initialization process for loading a signal into the TRC, a process of setting a rising edge flag when setting the rising edge flag when determining that the signal is a rising edge signal, and disabling a ring interrupt. Method characterized in that consisting of. 3. The signal detection process according to claim 2, wherein the signal detection process includes: a timing search process for decrementing the value of TRC by a predetermined period and searching whether the "high" section detection timer expires when the rising edge detection flag is set; A ring signal search process for enabling a ring interrupt upon determining that the timer has expired in the timer search process and searching for whether the ring detection mode is “high”, and a ring detection port is “high” during the input search process for the ring signal. And resetting the rising edge detection flag at the same time as setting the high edge detection request bit at the same time, and immediately resetting the rising edge detection flag when the detection port is "low".