USRobotics 33600, x2/56K user manual Introduction, How a Modem Works

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Introduction

How a Modem Works

A modem is a computer peripheral that allows you to communicate with other computers via telephone lines. Because ordinary telephone lines cannot carry digital information, a modem changes the digital data from your computer into analog signals, which can be transmitted much like voice signals. In a similar manner, the modem receiving the call then changes the analog signals back into digital data that the receiving computer can understand. This shift of digital data into analog signals and back again allows two computers to “speak” with one another. Called modulation/demodulation, this transformation of data and signals is how the modem received its name.

Sportster Winmodem 33600 & x2/56K - User's manual

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Contents User’s Manual 1997 Table of Contents Glossary Limited Warranty Appendix B Technical SpecificationsVoice Functions Appendix a Technical ReferenceHow a Modem Works IntroductionQuickly How Does Your Sportster Winmodem 33600 & x2/56K∗ Work ?Accurately Other FeaturesEfficiently With WindowsPackage Contents Plug and Play InstallationSportster Winmodem 33600 & x2/56K Installation Insert the Modem Into the Computer Installation ProcedurePlug in the power plug and turn the computer on Run the Modem’s Installation Program If you choose Then try This COM port This IRQ Running the Installation Program on a Windows 95 System Installing the Communications Software Page Changing Country Setup under Windows Page Installation Test Using the ModemFactory Settings Resetting the Modem to Factory Settings Remember the Following Points When Using the Modem Remarks on Using the ModemUn-Installing the Modem Page Symptom Solution TroubleshootingProblems and Solutions Modem does not Send AT commandsRespond when, Terminal mode, youUsing a certain Tone when you try toErrors There is no audibleModem Connection problemConnects itself Correctly toA fax, errors alter Transmission errorsIntercontinental Connections areBefore the Modems Connect If your PC reacts as Signals but fail toThough you are Online, but no callLink. If your screen displays random or garbage characters During Data TransfersDuring Fax Transmissions If You Are Still Having Problems Page Overview of Voice Functions Voice FunctionsSpeakerphone Application SettingsImplementing Voice Functions Voice ApplicationsInput/Output Source Selection Page Appendix a Technical Reference Main AT commandsBasic Command Set E0 Echo OFF E1 Modem displays keyboard commands Fn Sets online local echo of transmitted data ON/OFF Ln Controls speaker volume internals onlyHn Controls ON/OFF hook Displays the following informationVn Displays verbal/numeric result codes Xn Sets result code displayed. Default isFunctions Xn SettingResult Codes Advanced Command Set Sets Error Control ARQ 1200 bps and higher Enables/disables data compressionSets Guard Tone Sets Transmit DataTD flow controlSets pulse rotary dial make/break ratio Writes current configuration to Nvram templatesSets Receive Data RD hardware flow control Controls Data Set Ready DSR operationsRegisters Reg Default FunctionSets the number of seconds the modem Page Bit Value Result Reg Default Function Reg Default Function Page Value Bit 4 Bit ResultBit 128 Reserved Page Page Sportster Winmodem X2/56K Specifications Electrical power Electromagnetic Compatibility SafetyCE Mark Page Glossary Analog signalsAsynchronous transmission Baud rateBits BitBps BufferDigital signals Data modeError correction DuplexFallback Fax modeFlow control Local EchoRemote Echo ParityProtocol Serial transmission Terminal modeSynchronous transmission TerminalXON/XOFF Page Limited Warranty Advised of the Possibility of Such Damages Page 024.1388-00