ADSL modem for ADSL (asymmetric digital loop) provides a user data and demodulation data machines, highest support 8Mbps/s (downlink) and 1Mbps/s (uplink) rate, strong anti-jamming capability, suitable for ordinary families users. This product with a primary energy consumption of refrigerator similar, calorific value is bigger. Some types of products still contain routing functions. This product ratio between ISDN and LAN + fiber between. There is a phone line RJ - 11 holes and one or more RJ - 45 string hole, some types of products with radio functions.
Modem, is actually Modulator and Demodulator abbreviation. It was after the sender through modulation will digital signals into analog signals, and again at the receiving end through demodulation analog signal converting digital signal of a kind of device.
USES: inside a computer information is by "0" and "1" composed of digital signal, and in telephone wire transfer of but is only analog signals. Thus, when two computers to through telephone wires for data transmission, it need a device responsible for analog-to-digital conversion. The digital-to-analog converters is of a Modem. Computer in sending data, first by the Modem converts digital signals are converted to corresponding simulation signal, the process is called "modulation". After the modulated signals through phone carrier transferred to another computer via before, also want to recipient Modem undertakes the analog signal reduction for the computer can identify the digital signal, the process is called "demodulation". It is through such a "modulation" and "demodulation" analog-to-digital conversion process so as to realize the remote communication between two computers.
MODEM taxonomy
Generally speaking, according to Modem forms and installation, can can be divided into the following five categories:
1 and built-out type of a Modem
External extended Modem placed on chassis outside, through serial communication mouth and host connection. This kind of Modem convenient, easy installation, flashing dexterous facilitate the indicator of the working conditions of the monitoring of a Modem. But the external extended Modem need to use additional power and cables.
2, built-in Modem
Built-in Modem when installation needs, and to open box interrupt and the COM setting, installation is relatively complicated. This kind of Modem takes on the mainboard of expansion slot, but no extra power and cable, and the price is external extended Modem to cheaper.
3, PCMCIA plug-in of a Modem
Plug-in Modem is mainly used for laptops, volume dainty. Cooperate with mobile phones, can easily make mobile office.
4, rack-mountable of a Modem
Rack-mountable Modem equivalent a group of Modem focuses on a box or covering, and by a unified power supply. Rack-mountable Modem is mainly used in Internet/Intranet, telecommunication bureau, campus network, financial institutions and other network of computer and network center.
5, ISDN modems and CableModem
In addition to the above four common Modem outside, now have the ISDN modems and called CableModem modems, another is ADSL modems. CableModem through the cable TV cable signals, not only have demodulation functions, but also set a router, hubs, a bridge at a suit, theoretical transmission speed can reach more 10Mbps above. Through CableModem online, each user has a separate IP address, equivalent to have a personal line. At present, shenzhen cable television tianwei network company has launched this based on the Internet access service cable television, access rate for 2Mbps - 10Mbps!
New-type multi-functional of a MODEM
Modem was originally used for data transmission. However, as the user demand is growing and the fierce competition between manufacturers, on the market at present more and more appeared some "two-in-one", "three-in-one" of a Modem. These Modem besides can for data transmission outside, still have fax and voice transmission function.
1, fax mode (FaxModem)
Through Modem on fax, in addition to save a dedicated fax fees, benefits and many: can directly put inside a computer file fax the other party of the computer or fax machine, without first put the documents printed, Can docking received your fax convenient to store or editing, Can overcome the common fax machine caused by using thermal papers and cause the handwriting subside problem; Because of a Modem used error correction technology, fax quality is better than ordinary fax machine, especially for graphic fax is even more so. The current FaxModem mostly follow vladimir 29 and v. 17 fax protocol. One v. 29 support 9600bps fax rate, and v. 17 May support 14400bps fax rate.
2, speech mode (VoiceModem)
Speech pattern mainly provides telephone recording message and full-duplex hands-free conversations function, make telephone and computer as a whole. Here, mainly is a new voice transmission mode - DSVD (DigitalSimultaneousVoiceandData). DSVD is by Rockwell, Hayes, U.S.R obotics, Intel and other companies in 1995 raises an voice transmission standards, is the existing v. 42 error correction agreement the expansion. DSVD by adopting DigiTalk digital voice and data with preach technology, enable the Modem can in ordinary telephone line on one side of the data transmission of one side of the phone.
3, DSVDModem
DSVDModem retained 8K bandwidth (also some Modem retain 8.5 K) for pronunciation transmission bandwidth, the rest of the bandwidth is used in data transmission. Speech in a transmission before will be the first to compress and then required to transmit data comprehensive together, through phone carrier transmission to each other users. In the receiver, Modem first voice and data separated, and then the speech signal with decompression and/mode conversion, thus realize data/speech of simultaneous interpreters. DSVDModem the long-distance teaching, collaborative work, network game has broad prospect of application. But at present, because of the DSVDModem than common VoiceModem to expensive, and to realize data/speech with preach function, need each other, thus DSVDModem also used in a certain extent hindered DSVDModem popularization.
ADSL modem for ADSL (asymmetric digital loop) provides a user data and demodulation data machines, highest support 8Mbps/s (downlink) and 1Mbps/s (uplink) rate, strong anti-jamming capability, suitable for ordinary families users. This product with a primary energy consumption of refrigerator similar, calorific value is bigger. Some types of products still contain routing functions. This product ratio between ISDN and LAN + fiber between. There is a phone line RJ - 11 holes and one or more RJ - 45 string hole, some types of products with radio functions.ADSL MODEM detailed introductionModem, is actually Modulator and Demodulator abbreviation. It was after the sender through modulation will digital signals into analog signals, and again at the receiving end through demodulation analog signal converting digital signal of a kind of device.USES: inside a computer information is by "0" and "1" composed of digital signal, and in telephone wire transfer of but is only analog signals. Thus, when two computers to through telephone wires for data transmission, it need a device responsible for analog-to-digital conversion. The digital-to-analog converters is of a Modem. Computer in sending data, first by the Modem converts digital signals are converted to corresponding simulation signal, the process is called "modulation". After the modulated signals through phone carrier transferred to another computer via before, also want to recipient Modem undertakes the analog signal reduction for the computer can identify the digital signal, the process is called "demodulation". It is through such a "modulation" and "demodulation" analog-to-digital conversion process so as to realize the remote communication between two computers.MODEM taxonomyGenerally speaking, according to Modem forms and installation, can can be divided into the following five categories:1 and built-out type of a ModemExternal extended Modem placed on chassis outside, through serial communication mouth and host connection. This kind of Modem convenient, easy installation, flashing dexterous facilitate the indicator of the working conditions of the monitoring of a Modem. But the external extended Modem need to use additional power and cables.2, built-in ModemBuilt-in Modem when installation needs, and to open box interrupt and the COM setting, installation is relatively complicated. This kind of Modem takes on the mainboard of expansion slot, but no extra power and cable, and the price is external extended Modem to cheaper.3, PCMCIA plug-in of a ModemPlug-in Modem is mainly used for laptops, volume dainty. Cooperate with mobile phones, can easily make mobile office.4, rack-mountable of a ModemRack-mountable Modem equivalent a group of Modem focuses on a box or covering, and by a unified power supply. Rack-mountable Modem is mainly used in Internet/Intranet, telecommunication bureau, campus network, financial institutions and other network of computer and network center.5, ISDN modems and CableModemIn addition to the above four common Modem outside, now have the ISDN modems and called CableModem modems, another is ADSL modems. CableModem through the cable TV cable signals, not only have demodulation functions, but also set a router, hubs, a bridge at a suit, theoretical transmission speed can reach more 10Mbps above. Through CableModem online, each user has a separate IP address, equivalent to have a personal line. At present, shenzhen cable television tianwei network company has launched this based on the Internet access service cable television, access rate for 2Mbps - 10Mbps!New-type multi-functional of a MODEMModem was originally used for data transmission. However, as the user demand is growing and the fierce competition between manufacturers, on the market at present more and more appeared some "two-in-one", "three-in-one" of a Modem. These Modem besides can for data transmission outside, still have fax and voice transmission function.1, fax mode (FaxModem)Through Modem on fax, in addition to save a dedicated fax fees, benefits and many: can directly put inside a computer file fax the other party of the computer or fax machine, without first put the documents printed, Can docking received your fax convenient to store or editing, Can overcome the common fax machine caused by using thermal papers and cause the handwriting subside problem; Because of a Modem used error correction technology, fax quality is better than ordinary fax machine, especially for graphic fax is even more so. The current FaxModem mostly follow vladimir 29 and v. 17 fax protocol. One v. 29 support 9600bps fax rate, and v. 17 May support 14400bps fax rate.2, speech mode (VoiceModem)Speech pattern mainly provides telephone recording message and full-duplex hands-free conversations function, make telephone and computer as a whole. Here, mainly is a new voice transmission mode - DSVD (DigitalSimultaneousVoiceandData). DSVD is by Rockwell, Hayes, U.S.R obotics, Intel and other companies in 1995 raises an voice transmission standards, is the existing v. 42 error correction agreement the expansion. DSVD by adopting DigiTalk digital voice and data with preach technology, enable the Modem can in ordinary telephone line on one side of the data transmission of one side of the phone.3, DSVDModemDSVDModem retained 8K bandwidth (also some Modem retain 8.5 K) for pronunciation transmission bandwidth, the rest of the bandwidth is used in data transmission. Speech in a transmission before will be the first to compress and then required to transmit data comprehensive together, through phone carrier transmission to each other users. In the receiver, Modem first voice and data separated, and then the speech signal with decompression and/mode conversion, thus realize data/speech of simultaneous interpreters. DSVDModem the long-distance teaching, collaborative work, network game has broad prospect of application. But at present, because of the DSVDModem than common VoiceModem to expensive, and to realize data/speech with preach function, need each other, thus DSVDModem also used in a certain extent hindered DSVDModem popularization.
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