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ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING Multifunctional telephone technician device Berkut. Encyclopedia of radio electronics and electrical engineering
Encyclopedia of radio electronics and electrical engineering / Telephony The proposed device will help PBX specialists check and configure various components of switching equipment, subscriber installations, and automation equipment. It contains a telephone with advanced capabilities, a tone answering machine, a signal generator, and a frequency meter. The device is intended for use primarily by service personnel of automatic telephone exchanges (ATS). The purpose of its creation was to combine a number of necessary devices in one device and thereby replace the personal handset that every electrician, electromechanic, and sometimes engineer has. The main functions of the telephone set: type="disc">The device allows you to conduct a conversation, output audio frequency signals to the subscriber line, as well as to a separate output, measure interaction signals between automatic stations, and measure the frequency of signals as a frequency meter. Today, to perform these measurements, frequency counters, low-frequency signal generators, oscilloscopes, etc. are used. But in some cases, such use is questionable for a number of reasons. Firstly, it is difficult to carry a frequency meter or oscilloscope around the entire area, even if they are the most modern (their size allows this to be done). Even if you know in advance what you will need, bumping along Russian roads is not the best conditions for a measuring device of this class. Secondly, there is no point in measuring quantities with high accuracy (at least always) when, according to the standards, the parameters have wide tolerances. For example, the Station Answer signal has a frequency of 425 Hz, and the tolerance limits are ±25 Hz for some telephone exchanges. Why measure this signal with an accuracy of 425,05 Hz, for example, with a 43-34 frequency counter, if its value is allowed in the range from 400 to 450 Hz? As a result, in practice many parameters are not measured at all. When searching for a pair in a cable, another person with a device or a special tester with a low-frequency generator, a home-made low-frequency generator, or a certified low-frequency signal generator GZ-118 can be used. Using the proposed device will simplify the search procedure, and in some cases it is simply irreplaceable. None of the listed methods can supply a low-frequency signal to a line under voltage from the station battery without an additional device. The use of the proposed apparatus will make it possible to measure certain quantities with sufficient accuracy and quickly, in some cases without even going to the station and without resorting to expensive instruments. I do not propose to abandon the use of certified measuring instruments; I propose to use a highly specialized device for highly specialized measurements. As a result, service personnel will take with them an instrument weighing a maximum of 500 g instead of several instruments weighing 5 kg or more each. The gain in weight and energy consumption is dozens of times. The linear part corresponds to the linear part of the first class apparatus. The tone answering machine works like this: it receives three ringing signals with a level from 15 to 150 V with a frequency from 15 to 50 Hz and outputs a signal into the line with a frequency of 700 Hz, a level of 0,5 V into a load of 600 Ohms for 4 seconds. The low-frequency signal generator has a frequency range from 1 to 500 Hz. The duration of the pulse and pause is variable, from 0,1 to 999 ms. The number of repetitions is from 1 to 999 or infinite. The frequency measurement range of the “Station Answer” signal is from 350 to 500 Hz, and the “Rend Call” signal is from 15 to 50 Hz. Power supply - from a 220 V network (from an external power source) or from a battery. Current. consumption - 25 mA (peak value - 100 mA). The diagram of the device is shown in the figure.
The main element that controls the operation of the entire device is the DD1 microcontroller. All information is displayed on the HG1 indicator. The unit for generating a signal for switching bits for dynamic indication is assembled on a DD2 counter and VT13-VT21 transistors. Information is supplied to the indicator through port P1 of the DD1 controller and transistors VT5-VT12. At the beginning of each image output cycle, a counter reset signal DD3.5 comes from output P1 DD2. A tone signal to the line, as well as a signal for output, are generated at the output РЗ.О of the DD1 controller. The signal amplifier for the line is assembled on transistor VT26, and for output - on transistor VT1. The described signals, audible confirmation signals for pressing buttons and a call signal are sent via circuit R35, VT22, VT24 to the dynamic head BA1. The controller produces a loop closure signal at output RZ.Z, and a dialing signal at output P3.1. The call signal from the subscriber line is supplied through the diode bridge VD1 to the resistive divider R4R5. The attenuated signal through circuit R11C6R38 is supplied to the input of the amplifier on transistor VT25, and from it to input P3.4 of the DD1 controller. By adjusting resistor R41 you can adjust the sensitivity of this amplifier. Diodes VD2 and VD3 protect transistor VT25 from overloads. The “Station Answer” tone signal is removed from the load of the subscriber line - resistor R46 - and through the circuit R39C12 is supplied to the amplifier (transistor VT25). The amplifier on transistor VT2 is designed to amplify the signal received at the input in frequency meter mode. Through the C5R34 circuit, this signal is supplied to the input of the amplifier on the VT25 transistor. Power is supplied to controller DD1 and counter DD2 through a filter consisting of diode VD4 and capacitors C13, C14, C16-C19. Together, these components significantly reduce voltage surges. Loss of supply voltage from the network unit for up to 1 s does not interfere with the operation of the device. The conversation unit is a standard one, suitable for any telephone set. Lever switch SA1 switches the subscriber line from resistor R46 to the conversation unit. The keyboard is standard, 3x4, with a total of 12 buttons. Signals from the buttons are supplied to the DD1 controller in port P1. During the display, the controller analyzes the state of the buttons. If the button is pressed continuously, the corresponding segment on the indicator may be blanked. Now let's look at setting up the units of the device. Let's start with the fact that the first switch-on must be done without the DD1 controller. The left terminal of resistor R10 according to the diagram should be connected to the common wire, and the terminal of resistor R36 should be connected to the positive terminal of the power source. A variable resistor with a resistance of 3 kOhm and a power of at least 2 W must be connected in parallel to the terminals of the telephone line, setting the maximum resistance on it. An oscilloscope must be connected to the collector of the VT25 transistor. The common wire of the oscilloscope must be connected to the common wire of the device through a capacitor with a capacity of 0,47 μF with an operating voltage of at least 250 V. When connecting the power supply, the total current consumption should be no more than 10 mA. Now the left terminal of resistor R36 should be connected to the common wire, transistor VT23 will close, and VT4 will open. The device will load the telephone line. By turning the slider of resistor R41, you need to achieve the appearance of the “Station Reply” signal on the oscilloscope. Then a millivoltmeter is connected to the line. By turning the additional resistor slider, you check the sensitivity limits of the amplifier on the VT25 transistor. You shouldn’t get too carried away with sensitivity; in real work, the “Station Reply” signal has a sufficient level. The "Busy" and "KPV" signals are higher in level than the "Station Answer" signal. After setting up the amplifier on transistor VT25, do not touch the resistor R41 slider. Disconnect the millivoltmeter from the line, and then the additional resistor. Connect resistor R36 to the positive terminal of the power supply. The device will disconnect from the line. To control the passage of the ringing signal, you need to call from another device to the one you are setting up. The oscilloscope should display ringing signal pulses. Sensitivity can be adjusted by selecting resistors R4, R5, R11. To check the signal supply to the line, instead of the subscriber line, you need to connect a power source with a voltage of 15...20 V, rated for a current of 100 mA. Then apply a signal with a frequency of 2500 Hz with a level of at least 2 V from the low-frequency generator to the left terminal of resistor R35 according to the diagram. Sound should be heard in the BA1 dynamic head. Apply a low level to the left terminal of resistor R36, and connect headphones with a resistance of 300 Ohms to the line terminals through a capacitor. The signal must be heard in them. Its level should be about 0,5 V. If it differs from this value, select resistors R42 and R44. After this, you need to turn off the power to the device and install the microcontroller. Turn on the power. In the initial state, the device displays the number of numbers in RAM, the current time with seconds “5_12-3345”, polls the keyboard and the subscriber line. If there is no indication, check the presence of a signal with a frequency of 60 Hz at pin 9 of the DD1 controller and a signal with a frequency of 540 Hz at pin 11. If they are not there, you need to turn off the power, disconnect the indicated pins from the device circuits (for example, by bending these pins of the microcircuit) and again check for the presence of signals . If there are no pulses, check the operation of the master oscillator (signal with a frequency of 11,059 MHz at pin 4 of DD1). If the controller produces all the indicated signals, but there is still no indication, then the reason may be a malfunction of the DD2 counter. If there is no image in any category, you should check the corresponding resistors and transistors. The brightness of the indicator can be increased by using resistors R17-R33 of lower resistance. This will increase the total current consumption. When turning on the power, you must make preliminary settings: set the current time, timer response time, timer mode and numbers in RAM. Otherwise, the device will start working with the original settings. The clock will count down time from zero. The timer is set to 25 hours 25 minutes, i.e. the timer will never coincide with the current time. The numbers in RAM will be saved during operation. To dial a number, you need to dial the required number on the keyboard. The pause between the first and second digits should be no more than 2 s. "When dialing, the dialed digits are displayed on the indicator. After entering the fifth digit, the device will connect to the line and begin dialing the number. After dialing is completed, the device begins to count down the time and the message “-ONE-047-” will appear on the indicator. To talk, you need to switch the SA1 switch to the position "Conversation" If this is not done, after 20 seconds the device will disconnect from the line and return to its original state. The output signal from the generator is always fed into the line, output through the output amplifier and heard in the dynamic head. When performing incorrect actions, the device emits a long beep and displays “INCORRECT” on the indicator (for example, if all parameters for the generator are not set) and invites you to further actions: “-”. If, after auto-dialing, you do not switch the switch to the “Talk” position, the device will disconnect from the line 20 seconds after dialing the number and go to its original state. The device confirms the pressing of the buttons with a sound signal, and also automatically repeats the button press if the button is pressed continuously. When you enter more than 9 digits, the information on the indicator shifts to the left. The last 9 digits of the number are visible on the indicator. Now let's take a closer look at the instructions for using the device. PREPARING THE MACHINE FOR OPERATION Turn on the power. The device will beep. The indicator will successively display “tA-21 001”, “Уct CLOCK” and the prompt “-”. Enter "44MMZZDDG", where HH is hours, MM is minutes, ZZ is day, DD is month, G is year. Press the "*" button. The indicator will show “-YCt BUS!-” and a prompt to Enter “AABBEE”, where AABB is the alarm time or automatic dialing time, AA is hours, BB is minutes. If EE = 00, the alarm is set, if EE = 02, automatic dialing at the set time is set. Press "*". The indicator will show “RAM RAM-” and the “-” prompt. Enter the first number from 1 to 15 characters into RAM. The machine will dial this number when you take the handset off the machine. Press the "*" button. “K^ HH-MMSS” will appear on the indicator. This is the initial state. K - number of numbers in RAM, HH - hours, MM - minutes, SS - seconds. The clock shows the entered time. Enter the second number into RAM. This is the number to which the device will automatically dial using a timer. The following numbers do not need to be entered into RAM. They will be stored in RAM as you type during operation. Until the last number is entered into RAM, it is impossible to call a number from RAM. AUTOMATIC DIALING WHEN PHONE IS OFF THE DEVICE Remove the handset from the device. A "-" prompt appears. Do not dial a number on the keyboard for 2 seconds. The device will display the first number from RAM on the indicator, pause for 2 seconds to decide on further actions, and dial the number. AUTOMATIC DIALING BY NUMBER FROM RAM Dialing a number from RAM. Dial on the keyboard the serial number of the cell (1-5) where the required number is located. The dialed digit will be displayed on the indicator. The device will pause for 2 seconds and display the entire number on the indicator. After another 2 seconds, the device will connect to the line and begin dialing the number. During these 2 s, you can cancel the action using the “*” button, otherwise the device will dial the called number. Upon completion of dialing, the indicator will display the message “-ONE-ХХХ-”, where XXX is the duration in seconds. To talk, you need to move the switch to the “Talk” position at any stage of the connection process, but no later than 20 seconds after the device has completed dialing the number. MAKE A CALL TO ANY NUMBER Dial the required number on the keyboard. After dialing the 5th digit, the device will start dialing the number into the line. When the called party answers to talk, move the switch on the device to the “Talk” position. After dialing the number, the message “-ONE-ХХХ-” will appear on the indicator. Time is counted from the end of the set. AUTOMATIC DIALING ON THE LAST NUMBER The device's RAM stores the last number that the indicator showed. You can call it by pressing the "#" button. The device will display the number on the indicator and pause for 2 s. If you do not cancel the dialing with the "*" button, the device will dial the number. VIEWING NUMBERS IN RAM Enter the serial number of the RAM cell on the keyboard. The device will display the number on the indicator. Before 2 seconds have passed, press the “*” button. SOFT RESET FOR CORRECTION OF CLOCK, CALENDAR AND NUMBERS IN RAM Sequentially type “*##3” on the keyboard. The device will reset, go to the beginning and display “tA-21 001” on the indicator. It is necessary to complete all the steps that were performed in preparation for work. VIEW TIMER Dial "*##5" in sequence. The device will emit a sound signal and display “t AA-BB.E” on the indicator, where AA is the hour, BB is the minute, E is 0 or 2. To reset the readings, press the “*” button, or after 12 s the device will go into the initial state. RESETTING THE TIMER, MODE AND RAM NUMBERS Sequentially type “*##6” on the keyboard. The device will emit a sound signal and display the “Set Bud” indicator and the invitation “-”. Enter the time for the timer and mode, then all the numbers in RAM. FREQUENCY MEASUREMENT Connect the device to the line. To measure the “Station Answer” signal, sequentially dial “*##1” on the keyboard. The device will connect to the line and display “FF-ХХХHz” on the indicator, where XXX is the frequency of the “Station Answer” signal. The device will indicate the signal frequency for 10 seconds. After this, it will emit a double beep, disconnect from the line and return to its original state. If there is no signal at the input, the device emits a double beep, displays the message “-HEt SIG-” and returns to its initial state. To measure the frequency of the Calling signal, dial "*##2" sequentially on the keyboard. Call from another phone to the number to which the device is connected. The indicator will display the message "MF - XXHz" during the Calling signal, where XX - frequency of the received signal. When measuring an arbitrary frequency, do not connect the device to the line. Apply the measured signal to the input of the frequency meter. Enable frequency meter mode using one of the methods described above. Adjust the signal level with resistor R3 so that readings appear on the indicator. LOW-FREQUENCY OUTPUT ("GENERATOR") Consistently type “*#ХХХУУУУУТТТ##4” on the keyboard, where XXX is the duration of the pause, УУУ is the duration of the pulses in milliseconds, TTT is the number of repetitions of the sequence. If TTT = 000, the number of repetitions is infinite. The device will connect to the line and issue the dialed sequence. Upon completion, the device displays the message "ALL EXTRACTED." and returns to its original state. To repeat, type “##4” on the keyboard. After pressing the “#” button for the first time, the parameters will be displayed on the indicator. To issue a tone sequence, the subscriber needs to establish a connection with him in any way and move the switch to the “Talk” position. Follow the steps described at the beginning of the section. After issuing the sequence, the device will disconnect from the line itself. Since the same cells are used to store the 6th number in RAM and the generator parameters, after entering the generator parameters, the 6th number in RAM disappears. AUTO ANSWER When a call arrives, the device emits a sound signal and displays “CALL-X.” on the indicator, where X is the serial number of the received call. After receiving the third parcel, the device closes the loop, emits a signal into the line with a frequency of 700 Hz for 4 s, disconnects from the line and goes into its original state. If you want to talk, you need to flip the switch (pick up the handset). The answering machine will be interrupted. ALARM CLOCK If the current time coincides with the time set in the timer, the device emits an intermittent sound signal. You can turn it off by pressing any button, but in this case one is added to the timer, i.e. the timer is reset to a new time (set time + 1 minute). If you do not press any buttons, after one minute the device will stop beeping. The implemented method of trying to turn off the alarm clock is called the “running alarm clock”. If the person who wakes up tries to turn off the alarm clock “unconsciously”, the device resets the alarm clock to a new time - it moves forward one minute. MAKE A TIMER CALL (REMOTE ALARM) If the current time and the timer coincide, the device displays the second number from RAM and dials using it. After dialing the number, it outputs a sound signal on the line for 12 s, turns off and returns to the original mode. Literature
Author: I. Chernev, Lipetsk
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