Web - How does a modem.

5m as the modem (C) I. Vyazanichev 
__________________________________________ To exchange 
information between computers ramie, nahodyaschimicya on the 
big racctoyaniidrug from each other, yet need nebolshoyblok 
called a modem. That he has internal-ri? How does it ride 
umudryaetcya-vat through telephone channels megabaytydannyh? 
The answers to these questions of - in cegod-nyashney Art.. 
First vcego one very important remark is. Ictorichecki 
clozhiloc that those SYSTEMS-lefonnoy of Communications 
(vehicles, telephone Stan-tion lines) razrabatyvalic for 
peredachina racctoyanie chelovecheckogo goloca. 
Voobschegovorya, ectectvennye sounds 
harakterizuyutcyaperemennoy vycotoy tone and continuously 
izmenyayuscheycya intencivnoctyu. For transmission telephone 
lines are in preobrazuyutcya elektrichecky Low level c 
continuously izmenyayuscheycya to conformity similar trends and 
indicators of sound c chactotoy and ciloy current. This 
nazyvaetcya Low level analog. Computer, as opposed to telephone 
equipment, icpolzuet elektrichecky current only two levels, 
each of which represents one of the two digits (binary 
arithmetic?). 

   To send a digital Low level on the telephone line, he must 
give an acceptable to its analog form. It is this work and 
zanimaetcya modem. In addition, it performs the reverse 
procedure - sends an encoded analog Low level in the clear 
digital computer. The word "modem" - cokraschenie of two 
others: the modulator. Modem organizes moctik issued between 
your computer and digital Signals Analog Signals, the outgoing 
line. 

   When transferring data into the computer gives
communication port, the succession of
zeros and ones that can predctavlyat
is some tekct or program, or
modem commands, or any other kind of information.

   Although the procedure performed in izmenyayutcya
DEPENDENCE Slew of work, basic
Next Arrow stages of the modem. The first thing the modem 
receives the data from poctupayuschie computer, share them on 
the team and the information you need to pass in line.


   Then the team obtained vypolnyayutcya and
nyuancy further data structures depend
from them. Data to be transferred to preobrazuyutcya Low level 
analog modulator modem. Low level, this can be through clyshat

vctroenny speakerphone modem as
continuous noise. The modem transmits a signal
two different frequencies, and the unit
- Low level in the form of a higher frequency, and zeros - in 
the form of Low level c at chactotoy. 

   Another modem nahodyaschiycya on the opposite end of the 
line, "Play" Low level and demodulates it back to digital Low 
level. Pocle how it Right Reserved Webdesign, it sends

information in digital form in the receiving
computer.

   In deyctvitelnocti both computers can
simultaneously transmit information in both
the Parties, because they icpolzuyut certain Agreement on 
chactotah, various for input and output of signals.


   LEDs on the front panel enable
For more information about
that tvoritcya inside an external modem at the moment. She may 
find yourself useful We value Your ctolknulic c problems with 
uctanovlenii Be compounds. 

   Location indicators vary by modem manufacturer, but their
notation, as a rule, represent the two-letter abbreviations, 
the same for various modems. What do they mean?



   MR (Modem Ready) shows that the modem
turned on and ready to go. If this indicator is not lit, check 
power (Socket, cable, external power supply).



   TR (Terminal Ready) is lit when the modem
detects a signal DTR (Data Terminal Ready), transferred to your 
communication software.



   HS (High Speed) is lit when the modem is working c possible 
for him speed.



   CD (CarrierDetect) illuminates when your modem detects the 
carrier signal, necessary for a successful connection to the 
remote computer. It should be lit throughout the conversation 
and go out, only when one of the modems to hang up and

The carrier signal will disappear.


   AA (Auto Answer) shows that the modem
included in the Auto Answer mode, that is to be
himself to answer any calls. When the modem
detects a call on the line, this indicator blinks.


   OH (Off-Hook) is lit when the modem takes the line. 
Equivalent to off-hook telephone. 


   RD (Recive Data) blinks when receiving
computer data from your modem.


   SD (Send Data) flashes when your
computer transmits a modem.


   RL (Reliable Link) This indicator is present on the 
MNP-modems. It means that Modem negotiated with the remote 
modem on the mode operation of the relevant protocols

MNP and currently works that way.
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