Multi-Tech Systems MT3334SMI manual Local Analog Loopback Test V.54 Loop, Test procedure

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ModemModule Developer’s Guide

Introduction

Each time you turn on your modem, it performs an automatic self-test to ensure proper operation. Your modem also has three diagnostic tests: local analog loopback, remote digital loopback, and local digital loopback. These ITU-T V.54 loopback tests isolate telephone circuit and transmission problems.

In a loopback test, data from your computer loops through the circuits of your modem and/or a remote modem before it appears on your monitor. When the loop has been completed, the data on your PC’s monitor should match the original data.

The local analog loopback test allows you to verify that the modem’s transmitter and receiver circuits are functioning properly.

The local digital loopback allows you to verify that the local computer or terminal, the two modems, and the transmission line between them are functioning properly.

The remote digital loopback test allows you to verify that the remote computer or terminal, the remote modem, the serial ports, the telephone line, and the local modem are functioning properly.

Note: All loopback tests operate at all speeds except 300 bps.

Local Analog Loopback Test (V.54 Loop 3)

In this test, data from your computer or terminal is sent to your modem’s transmitter, converted into analog form, looped back to the modem’s receiver, converted into digital form, and then sent to your monitor for verification. No connection to the phone line is required.

AT&T1

CONNECT

UUUUUUUUU

UUU

Digital Analog

Computer or Terminal

Local MultiModem

Figure 6-1. Local analog loopback test.

Test procedure

1.Connect the modem to your computer. Using your communication program, set the desired baud rate and go into terminal mode.

2.Type AT&T1 and press ENTER. This places your modem in analog loopback mode in the originate mode. A CONNECT message should appear on your display. The modem is now out of command mode and in a pseudo-online mode.

3.Note that the CD LED is on. If you are set for 14,400 bps or higher, a speed LED should be on. If the CD LED is not on, there is a defect in your modem.

4.Enter characters 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 zeros. The characters entered should be displayed on your monitor. The TD and RD LEDs should flash when a character is entered.

5.To exit the test, type the escape sequence +++AT and press ENTER. This puts the modem in online command mode. Then type either AT&T or ATH to return to command mode.

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MT3334SMI

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Contents Model MT3334SMI Evaluation Kit Data/Fax Socketed ModemRevision Description PatentsContents Index Introduction and Description Features IntroductionProduct Description ModemModule Developer’s GuideTechnical Specifications Introduction and Description1200 bps Physical Dimensions MT3334SMI Physical DimensionsLED1-LED4 Test/Demo Board SpecificationsDS1 Test/Demo Board Block Diagram MT3334SMI Test/Demo Board Block DiagramMT3334SMI Pin-out MT3334SMI PinoutTypical Application MT3334SMI Design Considerations Hardware ConsiderationsRecommended Transceiver PC Board Layout ConsiderationsCalculating Z for Tip and Ring Traces Qty Name Description MT3334SMI PlacementKey Telecom Labeling Requirements FCC PartMultiple Listing ReregistrationIndustry Canada CS-03 AT Commands, S-Registers, and Result Codes Repeat Last Command AnswerAT Commands, S-Registers, and Result Codes Monitor Speaker Volume Monitor Speaker ModeReturn Online to Data Mode Result Codes Enable/DisableModem Reset Sr? Read Register ValueTone Dialing Result Code FormatCommand &Fn Load Factory Settings Asynchronous Communications ModeDisplay Current Settings Store Current ConfigurationCommand &Zy=x Store Dialing Command \An Select Maximum MNP Block Size\Bn Transmit Break \Jn Data Buffer Control\Nn Error Correction Mode Selection \Tn Inactivity Timer\Qn Flow Control Selection \Vn Protocol Result CodeCommand %DCn AT Command Control Command %En Fallback and Fall Forward ControlCommand +ES=n Enable Synchronous Buffered Mode Enter Setup PasswordRegister Unit Range Default Description RegistersS43 Result Codes Terse Verbose DescriptionClass 1 Fax Commands Class 1 Fax Command Summary Command DescriptionClass 1 Fax Commands Fax MOD Modulation Parameter Values CommandFunction Display Current Class Values Default Data modem Result Code MeaningFunction ModemModule Developer’s Guide CommandFunction Select Service Class Values Default Data mode Class 1 Fax Commands +FRS=? Enter+FRM=? Enter Sample Sessions Flow ControlResult Codes Action by Command Respone Local Modem Remote PC AT+FRH=3 No Carrier ModemModule Developer’s Guide Class 2 Fax Commands Class 2 Fax Command Implementation Class 2 Fax Commands EIA SP-2388 August+FAA +FAXERR+FCR +FBOR+FCQ +FDCC Fax Capability Parameters+FDCS Current Session Results+FDFFC Data Compression Format Conversion+FDIS Current Session Parameters+FDR +FDT+FECM +FET+FK +FLID+FLNFC +FLPL+FPTS +FRBC+FREL +FSPL+FHNG +FTSIMT3334SMI Remote Configuration Basic Procedure SetupChanging the Setup Password ModemModule User GuideRemote Configuration Changing the Remote Escape CharacterMT3334SMI Troubleshooting Test procedure Local Analog Loopback Test V.54 LoopTroubleshooting Remote Digital Loopback Test V.54 LoopLocal Digital Loopback Test V.54 Loop Local digital loopback testUpgrade Procedure Upgrade Overview Identify the Modem FirmwareIdentify the Current Firmware Version Multi-Tech Web SiteMulti-Tech BBS Download the Upgrade FileUpgrade Procedure Extract the Upgrade Files Use FlashPro to Upgrade Modem FirmwareRestore Your Parameters Clear Your Stored ParamentersAppendixes MT3334SMI FCC FAX Update International Modem RestrictionsCanadian Limitations Notice AppendixesNew Zealand Telecom Warning Notice EMC, Safety and Terminal Directive ComplianceEuropean Directives User Guide Statement Appendix B Multi-Tech Flash Programming Protocol IntroductionProgramming the Modem Handshake SequenceModemModule Developer’s Guide Program Sequence Other supported boot code commandsOther programming concerns Xxxx Intel Hex FormatData Record Eeee Extended Address RecordEnd of File Record Index IndexMT3334SM MT3334SMI MT3334SM
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