Multitech MT5634ZBA-USB manual Remote Digital Loopback Test V.54 Loop, Appendix C Loopback Tests

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Appendix C - Loopback Tests

Remote Digital Loopback Test (V.54 Loop 2)

The remote digital loopback test tests the phone lines and the circuits of both your modem and a remote modem. In this test, your modem must be on line with another modem that is set up to respond to a request for remote digital loopback. (Note that some modems might not support remote digital loopback or might have it disabled.) Data from your computer or terminal is transmitted through your modem and over the phone line to the remote modem, where it is then looped back to your modem.

AT&T6

OK UUUUUUUUU UUUUU

Digital Analog			Analog Digital

AT&T6

OK

Computer or Terminal Local MultiModem

Remote MultiModem Computer or Terminal

Figure C-2. Remote digital loopback test.

Test Procedure

1.Arrange to have &T6 set on the remote test modem.

2.Open your communications software and go into terminal mode. Type AT and press ENTER; you should get an OK message. Type AT\N and press ENTER to disable error correction.

3.Dial the remote modem and establish your online connection.

4.Type the escape sequence +++AT and press ENTER to bring your modem into online command mode.

5.Type AT&T6 and press ENTER. The local modem responds to this command by transmitting an unscrambled marking signal, which causes the remote modem to place itself in digital loopback mode. Then the local modem exits online command mode and enters data mode.

6.Enter data from your keyboard. For this test, typing multiple uppercase U characters is a good way to send an alternating test pattern of binary ones and zeroes. Data received by the remote modem enters its analog receiver, is converted to digital data, is reconverted into analog, and then is transmitted back to your modem. Your modem passes this test if the data received on your monitor is the same as the data entered from your keyboard.

7.To exit the test, type the escape sequence +++AT and press ENTER. This puts the modem in online command mode. The modem should respond with an OK message. If you wish to stay on line with the remote modem for normal data transmission, type AT&T and press ENTER to exit the test, then type ATO and press ENTER to return on line. If you wish to terminate the call, type ATH and press ENTER to hang up.

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Contents User Guide Trademarks Record of RevisionsContents Index Introduction and Description MT5634ZBA-USB User Guide IntroductionProduct Description Universal Serial Bus USBIntroduction and Description What Is in Your Modem Package?MT5634ZBA-USB User Guide Quick Start You supply Safety WarningsWhat You Will Need We supplyQuick Start Assemble the ModemInstall the Software USB Connection Connect the Modem to Your SystemLine Connection Phone ConnectionTest Your Modem Select the ModemFeatures What Can You Do with Your Modem? FeaturesData Telephone Line FaxRequired Equipment ComputerConnections Connecting to the Computer USBConnecting to the Telephone Line Line Connecting to a Telephone Set PhoneFront panel Front PanelMT5634ZBA-USB User Guide AT Commands, S-Registers and Result Codes AT Commands AT Command Summary Echo Online Data Characters Command DS=n Dial Stored Telephone NumberEcho Command Mode Characters Monitor Speaker VolumeCommand Sr=n Set Register Value Monitor Speaker ModeReturn Online to Data Mode Result Codes Enable/DisableModem Reset MT5634ZBA-USB User Guide Command Vn Result Code FormatCommand Xn Result Code Selection Command Yn Long Space DisconnectAsynchronous Communications Mode Load Factory SettingsCommand &Gn V.22bis Guard Tone Control Communications ModeSelect Stored Configuration for Hard Reset MT5634ZBA-USB User Guide Command &Tn V.54 Test CommandsDisplay Current Settings Command &Wn Store Current ConfigurationBreak Control Error Correction Mode SelectionModem Port Flow Control Data Buffer ControlProtocol Result Code Inactivity TimerCommand %Cn Data Compression Control Command %DCnAT Command ControlCommand%%%ATCRRemote Configuration Escape Sequence Command %En Fallback and Fall Forward ControlEnter Setup Password Command #S=x Store Setup PasswordRegisters S38 S37Rates K56flex Rates S89 S42S43 S48Terse Verbose Description Result CodesMT5634ZBA-USB User Guide Remote Configuration Setup Basic ProcedureChanging the Setup Password Changing the Remote Escape Character Remote ConfigurationMT5634ZBA-USB User Guide Troubleshooting Modem Does Not Respond to Commands None of the Indicators LightModem Dials But Cannot Connect TroubleshootingFax and Data Software Can’t Run at the Same Time Modem Cannot Connect When AnsweringModem Disconnects While Online Modem Doesn’t Work with Caller IDAppendixes FCC Regulations for Telephone Line Interconnection Appendix a Regulatory ComplianceIndustry Canada Class B StatementFAX Branding Statement Canadian Limitations NoticeInternational Modem Restrictions European DirectivesNew Zealand Telecom Warning Notice Appendix B Technical Specifications ITU-T V.32bis/V.32 Carrier Frequencies ConnectorsCarrier Frequencies ITU-T Weight Diagnostics Indicators DimensionsIntroduction Appendix C Loopback TestsLocal Analog Loopback Test V.54 Loop Figure C-1. Local analog loopback test Test ProcedureAppendix C Loopback Tests Remote Digital Loopback Test V.54 LoopLocal Digital Loopback Test V.54 Loop Figure C-3. Local digital loopback test Test ProcedureService Appendix D Warranty, Service, and Technical SupportLimited Warranty Online Warranty RegistrationTo Download a File Technical SupportMulti-Tech BBS To Log on to the Multi-Tech BBSAbout the Internet About the Multi-Tech Fax-Back ServiceIndex Index MT5634ZBA-USB User Guide