If you've ever been fortunate to be connected to the internet in the late 90s and early 2000s in Vietnam, you may have noticed these sounds. This is the sound characteristic for internet connection based on Dial-Up dial technology. Although these loud and loud buzzing words can make many people uncomfortable, it is the sound signal for, you are about to become part of the internet.
Audio dial up internet connection
Although those strange sounds have become a part of internet history and become familiar to many people, its meaning remains a mystery to most of us. So what do these sounds mean?
Basically, the sounds we hear are handshake, also known as the telephone conversation between two modems. Due to the use of desk phone lines to connect, modems need a separate language to confirm that the other end is also a computer, not a human.
Hello, is that modem?
Like your name, to connect to the internet via a dial-up modem, your modem will actually have to dial-up to a phone number and on the other end, your modem ISP service will "pick up". That's why the headline is similar to the dial on the landline phone in the first part of this sound sequence.
After two modems on both sides of the wire recognize each other, they will begin to exchange short binary data to assess which type of protocol is suitable for communication. This stage is called the V.8 bis transaction.
Destruction of echoes
After that, the modem will have to solve the echo cancellation problem. When people talk on the phone, usually only one of them will speak and the other will listen. The telephone network exploits this factor and temporarily silences the reception channel to suppress any echoes that may interfere with the speaker's voice.
But modems can "talk" together (it's called full duplex). Therefore, the answering modem will be placed in a special tone to disable any echo cancellation circuit on the call line. This tone is also periodically converted 180 degrees to disable another circuit, called the echo cancellation circuit.
Find the appropriate modulation mode
Modems will now list supported modulation (signal conversion) modes and find out if both modes are available. They will also probe the line by emitting test tones to see how it responds to the tone of different frequencies, and how the line degrades the signal. Modems will exchange the received results and decide the speed to match the line.
Concluding the confession
After this "talk" screen, the modem will switch to mixing data. They let their data run through a special mixing formula before transmitting so that the energy distribution is more uniform and ensures there is no model below the optimal level when transmitting. They listen to each other by sending a series of 1-second binary samples and adjusting their equalizer to optimize the incoming signal.
At this point, when the data connection has been established, the speaker on your modem will stop emitting sounds to avoid annoying and exposing data, but in fact, the tones exchanged between the two modems. still constantly being released and received.
The signaling method tells you, everything is fine
You hear the sound coming from this exchange because modem manufacturers have turned on the speakerphone by default when connected so you can hear it and see if any error arises in the process. connection (busy signal, wrong number, someone picks up instead of answering modem, …). If you are a little skilled, you can turn off these sounds by sending the AT M0 command line before dialing.
Technically, even DSL connections. Broadband also made this buzzing sound during the connection process, however, with data rates thousands of times larger than dial-up connections, these sounds are too fast to hear the frequency of human ears that cannot be heard, so broadband routers are not equipped with external speakers to emit those sounds.
The images only carry the nostalgic meaning of an old time.
In Vietnam, 15 years after its launch, until 2012, when VNPT Post and Telecommunications Group announced to stop providing Dial-Up internet connection services, its typical "headlines". also officially disappeared in Vietnam market.
Slow speed, unstable connection and very expensive of Dial-Up technology compared to Vietnamese users' income at that time, it is hard to find someone to regret the departure of this technology. But because of these disadvantages, perhaps only a dial-up connection gives users the feeling of being thrilled and happy when accessing the internet successfully.
Refer to the Windytan Blog