Long-distance communication is the transmission of telephone and other signals over long distances. It is carried out through communication channels connecting communication stations (nodes) to each other. A communication channel is a set of technical linear and station devices through which it is possible to transmit variable electricity telephone, telegraph or other signal.
The telephone channel is organized via the voice frequency channel of the primary EACC network with a bandwidth from 300 to 3400 Hz. When using a physical circuit, the communication range is limited mainly by the amount of signal attenuation. Since the signal power at the microphone output of the transmitting telephone is approximately 1 mW, and the receiving telephone provides satisfactory audibility at a power level of 0.001 mW, then when direct inclusion telephone sets into the line, the signal reduction should be no more than 1000 times. The communication range is:
on an overhead circuit with copper wires with a diameter of 3-4 mm - 300-500 km;
on an overhead chain with steel wires with a diameter of 4-5 mm - 70-90 km;
on a cable chain, with copper conductors with a diameter of 1-1.2 mm - 20-30 km.
The communication range can be increased by reducing attenuation (for example, increasing the diameter of the wires), increasing the transmission or reception level (turning on amplifiers). Amplifiers that amplify tonal frequencies are called telephone amplifiers. To increase the communication range, intermediate amplifiers are connected to the circuit at certain distances. The section of the circuit located between two adjacent intermediate amplifiers, between the transmitter and the amplifier, or between the receiver and the amplifier is called the amplification section. The attenuation in each amplification section is compensated by the gain of the corresponding intermediate amplifier.
When telephoning, the same telephone set is either a transmitter or a receiver, therefore, to transmit information in both directions, it is necessary to have two identical one-way channels independent of each other. Since amplifiers amplify currents in only one direction of transmission, they are connected to a two-wire city telephone circuit using a differential DS system. A two-way telephone channel, which consists of two one-way channels, is shown in Fig. 66. Signal transmission in different directions is carried out through two different two-wire physical circuits. Such a telephone channel is called a channel of a single-side four-wire system. The name "single-band" means that transmission in both directions is carried out by currents in the same frequency band.
A two-way telephone call can also be organized using a single two-wire physical circuit. To do this, it is necessary to install two differential systems and two amplifiers, called duplex amplifiers, at each amplification point. Such a channel is called a channel of a single-sided two-wire system. Differential systems suppress currents feedback in duplex amplifiers due to the equality of the resistances of the balanced circuits and the input resistances of the corresponding sections of the circuit. However, complete suppression of feedback currents cannot be achieved; some of them pass from one section of the circuit to another, amplified by amplifiers. If the total feedback current is large enough, conditions will be created for the self-excitation of a duplex amplifier. To prevent this phenomenon, the number of duplex amplifiers connected in series in the circuit should not exceed five or six, which limits the communication range. Therefore, for long-distance communication, a four-wire channel is used, since it has only one feedback circuit (through differential systems of final amplifiers) regardless of the number of intermediate amplifiers included in the channel. The disadvantage of a four-wire channel is the need to use four wires instead of two to organize it.

Long-distance communication by country

Azerbaijan

Belarus

Georgia

Kazakhstan

Moldova

Russia

In the Law “On Communications,” which came into force on January 1, 2004, but only really came into effect at the beginning of 2005 (the necessary by-laws were adopted), the Ministry of Information and Communications proposed a horizontal model for liberalizing the long-distance communication market. To obtain an alternative long-distance license, the telephone company must build access points (that is, be present) in all regions of Russia.

Carrier selection codes

Currently, codes for selecting a telecom operator when choosing the latter, to provide subscribers with access to long-distance and international services telephone communication, assigned to the following companies:

№	Operator	Area code	International code	Universal code 8-15-XX	CPC category
1	Rostelecom "	55	10	55	1
2	OJSC "Mobile TeleSystems"	23	28	23	2
3	OJSC "Vympel-Communications"	51	56	51	3
4	Equant LLC	54	59	59	4
5	CJSC TransTeleCom Company	52	57	57	6
6	CJSC "Sinterra"	22	27	22	7
7	JSC "ARKTEL"	21	26	21	8
8	OJSC "Interregional TransitTelecom"	53	58	19	9
9	O.S.S.-Telecom LLC	-	-	14	-
10	OJSC "MegaFon"	-	-	15	-
11	CJSC "OptiTelecom"	-	-	16	-
12	Mobifon-2000 LLC	-	-	17	-
13	LLC "CONNECT"	24	29	20	-

Dialing procedure

From March 1, 2006, the procedure for dialing long-distance or international number compared to the old one.

In the old order, long-distance and international calls were made by dialing the number 8 (at telephone exchanges with automatic long distance communication, that is, on most of them), and the call went through the Rostelecom operator. In the new procedure, it is not enough to dial “8”; you must then select the telecom operator through which the call will be routed (a two-digit number), and then the number. In addition, you can switch to one of the operators on a permanent basis (Pre-Select mode), in this case the dialing order is the old one, simply through “8”, and the telecom operator is the same all the time. Even in this mode, it is possible to make calls through other operators by simply selecting code 15 after "8" and then following the new pattern.

In a number of regions, a subscriber can select the Pre-Select mode without visiting the company’s office by calling a special automatic number. This is possible in the companies MGTS (Moscow), Dalsvyaz (all subjects of the Far Eastern Federal District), Uralsvyazinform (all subjects of the Ural Federal District), Bashinformsvyaz (Bashkortostan), Tattelecom (Tatarstan).

Alternative operators conduct a campaign to call subscribers, offering them to switch to their services directly during the call - for this, verbal consent and selection through an automatic number are sufficient. Also, any subscriber can make long-distance calls, each time choosing an operator for this call (Hot-Choice mode).

In mode Pre-Select, when a subscriber makes a choice in favor of one operator and uses only its services, the dialing order is preserved:

• 8-beep-ABC-xxx - for long-distance calls (where: ABC - city code, xxx - subscriber number)
• 8-beep-10-country code-xxx - for an international call (where: xxx - city code and subscriber number)

In mode Hot-Choice the subscriber selects an operator for each call:

• 8-beep - long-distance operator code - АВС-ххх - for long-distance calls (where: АВС - city code, ххх - subscriber number)
• 8-beep - international operator code - country code - xxx - for an international call (where: xxx - city code and subscriber number)

• 8-beep-15-universal operator code-8-АВС-ххх - for long-distance calls (where: АВС - city code, ххх - subscriber number)
• 8-beep-15-universal operator code-810-country code-xxx - for an international call (where: xxx - city code and subscriber number)

When calling to Cell phones The same rules apply from stationary devices with federal numbers.

• 8-beep-long-distance operator code-xxx-xxxxxxx (xxx-xxxxxxx - mobile phone)

• 8-beep-15-universal operator code-xxx-xxxxxxx (xxx-xxxxxxx - mobile phone)

Ukraine

see also

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Notes

Links

• Long distance communication- article from the Great Soviet Encyclopedia.
• Long-distance communication (Russian market): tadviser.ru/index.php/Articles: Long-distance_communication (Russian_market)

Excerpt characterizing Long-distance communication

- Who are you?
- I'm an officer. “I would like to see,” said the Russian pleasant and lordly voice.
Mavra Kuzminishna unlocked the gate. And a round-faced officer, about eighteen years old, with a face similar to the Rostovs, entered the courtyard.
- We left, father. “We deigned to leave at vespers yesterday,” Mavra Kuzmipishna said affectionately.
The young officer, standing at the gate, as if hesitant to enter or not to enter, clicked his tongue.
“Oh, what a shame!..” he said. - I wish I had yesterday... Oh, what a pity!..
Mavra Kuzminishna, meanwhile, carefully and sympathetically examined the familiar features of the Rostov breed in the face of the young man, and the tattered overcoat, and the worn-out boots that he was wearing.
- Why did you need a count? – she asked.
- Yeah... what to do! - the officer said with annoyance and grabbed the gate, as if intending to leave. He stopped again, undecided.
– Do you see? - he suddenly said. “I am a relative of the count, and he has always been very kind to me.” So, you see (he looked at his cloak and boots with a kind and cheerful smile), and he was worn out, and there was no money; so I wanted to ask the Count...
Mavra Kuzminishna did not let him finish.
- You should wait a minute, father. Just a minute,” she said. And as soon as the officer released his hand from the gate, Mavra Kuzminishna turned and with a quick old woman’s step walked into the backyard to her outbuilding.
While Mavra Kuzminishna was running to her place, the officer, with his head down and looking at his torn boots, smiling slightly, walked around the yard. “What a pity that I didn’t find my uncle. What a nice old lady! Where did she run? And how can I find out which streets are the closest to catch up with the regiment, which should now approach Rogozhskaya? - the young officer thought at this time. Mavra Kuzminishna, with a frightened and at the same time determined face, carrying a folded checkered handkerchief in her hands, came out from around the corner. Without walking a few steps, she unfolded the handkerchief, took out a white twenty-five-ruble note from it and hastily gave it to the officer.
“If their Lordships were at home, it would be known, they would definitely be related, but maybe... now...” Mavra Kuzminishna became shy and confused. But the officer, without refusing and without haste, took the piece of paper and thanked Mavra Kuzminishna. “As if the count were at home,” Mavra Kuzminishna kept saying apologetically. - Christ is with you, father! God bless you,” said Mavra Kuzminishna, bowing and seeing him off. The officer, as if laughing at himself, smiling and shaking his head, ran almost at a trot through the empty streets to catch up with his regiment to the Yauzsky Bridge.
And Mavra Kuzminishna stood for a long time with wet eyes in front of the closed gate, thoughtfully shaking her head and feeling an unexpected surge of maternal tenderness and pity for the officer unknown to her.

In the unfinished house on Varvarka, below which there was a drinking house, drunken screams and songs were heard. About ten factory workers were sitting on benches near tables in a small dirty room. All of them, drunk, sweaty, with dull eyes, straining and opening their mouths wide, sang some kind of song. They sang separately, with difficulty, with effort, obviously not because they wanted to sing, but only to prove that they were drunk and partying. One of them, a tall, blond fellow in a clear blue scent, stood above them. His face with a thin, straight nose would be beautiful if it were not for his thin, pursed, constantly moving lips and dull, frowning, motionless eyes. He stood over those who were singing, and, apparently imagining something, solemnly and angularly waved his white hand rolled up to the elbow over their heads, the dirty fingers of which he unnaturally tried to spread out. The sleeve of his tunic was constantly falling down, and the fellow diligently rolled it up again with his left hand, as if there was something particularly important in the fact that this white, sinewy, waving arm was certainly bare. In the middle of the song, screams of fighting and blows were heard in the hallway and on the porch. The tall fellow waved his hand.
- Sabbath! – he shouted imperiously. - Fight, guys! - And he, without ceasing to roll up his sleeve, went out onto the porch.
The factory workers followed him. The factory workers, who were drinking in the tavern that morning under the leadership of a tall fellow, brought skins from the factory to the kisser, and for this they were given wine. The blacksmiths from the neighboring cousins, hearing the noise in the tavern and believing that the tavern was broken, wanted to force their way into it. A fight broke out on the porch.
The kisser was fighting with the blacksmith at the door, and while the factory workers were coming out, the blacksmith broke away from the kisser and fell face down on the pavement.
Another blacksmith was rushing through the door, leaning on the kisser with his chest.
The fellow with his sleeve rolled up hit the blacksmith in the face as he rushed through the door and shouted wildly:
- Guys! They're beating our people!
At this time, the first blacksmith rose from the ground and, scratching the blood on his broken face, shouted in a crying voice:
- Guard! Killed!.. Killed a man! Brothers!..
- Oh, fathers, they killed him to death, they killed a man! - the woman squealed as she came out of the neighboring gate. A crowd of people gathered around the bloody blacksmith.
“It’s not enough that you robbed people, took off their shirts,” said someone’s voice, turning to the kisser, “why did you kill a person?” Robber!
The tall fellow, standing on the porch, looked with dull eyes first at the kisser, then at the blacksmiths, as if wondering who he should fight with now.
- Murderer! – he suddenly shouted at the kisser. - Knit it, guys!
- Why, I tied up one such and such! - the kisser shouted, waving off the people who attacked him, and, tearing off his hat, he threw it on the ground. As if this action had some mysteriously threatening significance, the factory workers who surrounded the kisser stopped in indecision.
“Brother, I know the order very well.” I'll get to the private part. Do you think I won't make it? Nowadays no one is ordered to commit robbery! – the kisser shouted, raising his hat.

Long distance communication- telephone-telegraph communication cable And radio relay lines between two points located at a far (almost unlimited) distance from each other. The term "long-distance communication" originated in transmission technology electrical signals By wired communication lines.

Story

Long-distance communication by country

Azerbaijan

Main article: Communications in Azerbaijan

Belarus

Georgia

Kazakhstan

Moldova

Russia

In the old order, long-distance and international calls were made by dialing the number 8 (at telephone exchanges with automatic long-distance communication, that is, at most of them), and the call went through the Rostelecom operator. In the new procedure, it is not enough to dial “8”; you must then select the telecom operator through which the call will be routed (a two-digit number), and then the number. In addition, you can switch to one of the operators on a permanent basis (Pre-Select mode), in this case the dialing order is the old one, simply through “8”, and the telecom operator is the same all the time. Even in this mode, it is possible to make calls through other operators by simply selecting code 15 after "8" and then following the new pattern.

In a number of regions, a subscriber can select the Pre-Select mode without visiting the company’s office by calling a special automatic number. This is possible in the companies MGTS (Moscow), Dalsvyaz (all subjects of the Far Eastern Federal District), Uralsvyazinform (all subjects of the Ural Federal District), Bashinformsvyaz (Bashkortostan), Tattelecom (Tatarstan).

Alternative operators conduct a campaign to call subscribers, offering them to switch to their services directly during the call - for this, verbal consent and selection through an automatic number are sufficient. Also, any subscriber can make long-distance calls, each time choosing an operator for this call (Hot-Choice mode).

In mode Pre-Select, when a subscriber makes a choice in favor of one operator and uses only its services, the dialing order is preserved:

• 8-beep-ABC-xxx - for long-distance calls (where: ABC - city code, xxx - subscriber number)
• 8-beep-10-country code-xxx - for an international call (where: xxx - city code and subscriber number)

In mode Hot-Choice the subscriber selects an operator for each call:

• 8-beep - long-distance operator code - АВС-ххх - for long-distance calls (where: АВС - city code, ххх - subscriber number)
• 8-beep - international operator code - country code - xxx - for an international call (where: xxx - city code and subscriber number)

• 8-beep-15-universal operator code-8-АВС-ххх - for long-distance calls (where: АВС - city code, ххх - subscriber number)
• 8-beep-15-universal operator code-810-country code-xxx - for an international call (where: xxx - city code and subscriber number)

When calling mobile phones from landlines with federal numbers, the same rules apply.

• 8-beep-long-distance operator code-xxx-xxxxxxx (xxx-xxxxxxx - mobile phone)

• 8-beep-15-universal operator code-xxx-xxxxxxx (xxx-xxxxxxx - mobile phone)