New Mind | The Modem: Building The Internet With Sound @NewMind | Uploaded 2 years ago | Updated 11 hours ago
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THE INTERNET
ARPANET was initially created to facilitate communications among government agencies and research institutions. The civilian ARPANET would eventually be migrated to a more modernized parallel network called NSFNET. Around this time, the restrictions on the commercial use of NSFNET would be lifted and with it came the emergence of the commercial internet service provider industry.
This shift to commercialization became the catalyst for a massive influx of money, technical advancement, and the proliferation of access that transitioned the early internet from the militarys technological marvel to the massive communications apparatus that infiltrates every aspect of our lives today.
BAUD RATE
The baud units definition would be revised and redefined formally in 1926, to represent the number of distinct symbol changes made to a transmission medium per second.
THE FIRST MODEMS
Derived from the term modulator-demodulator, a modem converts digital data into a signal that is suitable for a transmission medium. A year later, a commercial variant of the SAGE modem would be introduced to the public as the Bell 101 Dataset.
FSK
In 1962, the underlying technology of the modem would split from that of teleprinters with the introduction of the Bell 103 dataset by AT&T. Because the Bell 103 was now fully electronic, a new modulation method was introduced that was based on audio frequency-shift keying to encode data. In frequency shift keying a specific transmitted frequency is used to denote a binary state of the transmission medium.
By the mid 1970s, the baud rate of frequency shift keying modems would be pushed even higher with the introduction of 600 baud modems that could operate at 1200baud when used in one directional communication, or half-duplex mode.
HAYES SMARTMODEM
The Smartmodem introduced a command language which allowed the computer to make control requests that included telephony commands, over the same interface used for the data connection.
The mechanics allowed the modem to switch between command mode and data mode by transmitting an escape sequence of 3 plus symbols. From this, the Hayes smart modem quickly grew in popularity during the mid 1980s, inherently making the command set used by it, the Hayes command set, the de facto standard of modem control.
QAM
As the early 1980s progressed, manufacturers started to push their modem speeds past 1200 bps. In 1984, a new form of modulation called quadrature amplitude modulation would be introduced to the market. Quadrature amplitude modulation is an extension of phase shift keying that adds additional symbol encoding density per baud unit, by overlapping amplitude levels with phase states. The first modem standard to implement quadrature amplitude modulation was ITU V. 22bis employed a variation of the modulation, known as 16-QAM to encode 16 different symbols, or 4 bits of data within each baud unit, using a combination of 3 amplitude levels and 12 phases.
TRELLIS
Trellis code modulation differs dramatically from previous modulation techniques, in that it does not transmit data directly. A state machine based algorithm is then used to encode data into a stream of possible transitions between branches of the partition set. This transition data is used to recreate all possible branch transitions in a topology that is similar to a trellis. From this, using a predetermined rule for path selection, the most likely branch transition path is chosen and used to recreate the transmitted data.
HIGH SPEED MODEMS
By 1994, baud rates would be increased to 3,429 symbols per second with up to 10 bits per symbol encoding now becoming possible. The dramatic boost in data rates created by TCM directly changed the look and feel of the growing internet.
56K
In early 1997, the modem would get one last boost in bitrate with the introduction of the first 56k dial-up modems. Pushing speeds above 33.6kps proved to be extraordinarily challenging as that process that digitized telephone audios signals for routing by telecommunications infrastructure made it very difficult for denser data transmissions to survive the digitizing process. This difficulty led modem manufacturers to abandon pushing analog-end bitrate speeds higher. Initially there were two competing standards for 56k technology, US Robotics' X2 modem and the K56Flex modem developed by Lucent Technologies and Motorola.
Both competing products began to permeate the market at the beginning of 1997, and by October nearly 50% of all ISPs within the United States supported some form of 56k technology. V.90 merged the two competing designs into an entirely new standard that would receive strong industry support.
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THE INTERNET
ARPANET was initially created to facilitate communications among government agencies and research institutions. The civilian ARPANET would eventually be migrated to a more modernized parallel network called NSFNET. Around this time, the restrictions on the commercial use of NSFNET would be lifted and with it came the emergence of the commercial internet service provider industry.
This shift to commercialization became the catalyst for a massive influx of money, technical advancement, and the proliferation of access that transitioned the early internet from the militarys technological marvel to the massive communications apparatus that infiltrates every aspect of our lives today.
BAUD RATE
The baud units definition would be revised and redefined formally in 1926, to represent the number of distinct symbol changes made to a transmission medium per second.
THE FIRST MODEMS
Derived from the term modulator-demodulator, a modem converts digital data into a signal that is suitable for a transmission medium. A year later, a commercial variant of the SAGE modem would be introduced to the public as the Bell 101 Dataset.
FSK
In 1962, the underlying technology of the modem would split from that of teleprinters with the introduction of the Bell 103 dataset by AT&T. Because the Bell 103 was now fully electronic, a new modulation method was introduced that was based on audio frequency-shift keying to encode data. In frequency shift keying a specific transmitted frequency is used to denote a binary state of the transmission medium.
By the mid 1970s, the baud rate of frequency shift keying modems would be pushed even higher with the introduction of 600 baud modems that could operate at 1200baud when used in one directional communication, or half-duplex mode.
HAYES SMARTMODEM
The Smartmodem introduced a command language which allowed the computer to make control requests that included telephony commands, over the same interface used for the data connection.
The mechanics allowed the modem to switch between command mode and data mode by transmitting an escape sequence of 3 plus symbols. From this, the Hayes smart modem quickly grew in popularity during the mid 1980s, inherently making the command set used by it, the Hayes command set, the de facto standard of modem control.
QAM
As the early 1980s progressed, manufacturers started to push their modem speeds past 1200 bps. In 1984, a new form of modulation called quadrature amplitude modulation would be introduced to the market. Quadrature amplitude modulation is an extension of phase shift keying that adds additional symbol encoding density per baud unit, by overlapping amplitude levels with phase states. The first modem standard to implement quadrature amplitude modulation was ITU V. 22bis employed a variation of the modulation, known as 16-QAM to encode 16 different symbols, or 4 bits of data within each baud unit, using a combination of 3 amplitude levels and 12 phases.
TRELLIS
Trellis code modulation differs dramatically from previous modulation techniques, in that it does not transmit data directly. A state machine based algorithm is then used to encode data into a stream of possible transitions between branches of the partition set. This transition data is used to recreate all possible branch transitions in a topology that is similar to a trellis. From this, using a predetermined rule for path selection, the most likely branch transition path is chosen and used to recreate the transmitted data.
HIGH SPEED MODEMS
By 1994, baud rates would be increased to 3,429 symbols per second with up to 10 bits per symbol encoding now becoming possible. The dramatic boost in data rates created by TCM directly changed the look and feel of the growing internet.
56K
In early 1997, the modem would get one last boost in bitrate with the introduction of the first 56k dial-up modems. Pushing speeds above 33.6kps proved to be extraordinarily challenging as that process that digitized telephone audios signals for routing by telecommunications infrastructure made it very difficult for denser data transmissions to survive the digitizing process. This difficulty led modem manufacturers to abandon pushing analog-end bitrate speeds higher. Initially there were two competing standards for 56k technology, US Robotics' X2 modem and the K56Flex modem developed by Lucent Technologies and Motorola.
Both competing products began to permeate the market at the beginning of 1997, and by October nearly 50% of all ISPs within the United States supported some form of 56k technology. V.90 merged the two competing designs into an entirely new standard that would receive strong industry support.
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