3Com 980/000048/001 manual Perform a local analogue loop test

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Troubleshooting Guide

3-5

Intermittent disconnects, high error rates, or excessive retransmissions

Perform a remote digital loop test as described in the AccessBuilder 7000 AT Command Reference.

Modem establishes and disconnects a call

You may have a poor telephone line connection. Disconnect and dial again.

The remote modem may have encountered an error correction disconnect, where the modem is configured to establish a call using error correction. If the modem cannot negotiate error correction, then a disconnect occurs.

The remote modem may be in a forced error correction mode (disconnect if there is no error control). Reconfigure your modem to V.42/MNP or buffer correction and try again.

Perform a local analogue loop test.

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Contents Accessbuilder Triple Modem Module User Guide 3Com Corporation 5400 Bayfront Plaza Santa Clara, California Important Safety Information Wichtige Sicherheitshinweise ’INFORMATION DE Sécurité Importante Page Contents Modem Specification and Interface PIN Assignments Index Limited Warranty FCC Class a Verification Statement Page Introduction How to Use This GuideThis table shows where to find specific information About this GuideText conventions used in this guide are ConventionsIcon conventions that are used throughout this guide are Keep the unit away from radiators and heat sources Additional Safety InformationAbout this Guide Triple Modem Module Support for dial-up transmission protocols Principal FeaturesImplementation of V.32terbo Triple Modem Module Modem Connections To The Central Site Typical ApplicationsRegistering Ownership of your Triple Modem Module Pack Contents ChecklistPre-installation Requirements Triple Modem Module Overview Installation and OperationInstalling The Module Installing The Rear Card Installing the Rear CardExample of Installing a Front Card Installing the Front CardConnecting the Cables Front Panel LEDs Front Panel LEDs Installation and Operation Modem Health TroubleshootingTroubleshooting Guide Modem DTE Connection Modem does not accept or echo back AT commandsModem Telephone Line Connection Troubleshooting Perform a local analogue loop test Private-line Operation Dial Backup OperationOn-line Operation Interface PIN Assignments Modem SpecificationTransmitter / Receiver Specifications Autodial Autoanswer Protocols Physical DescriptionGeneral Approvals Requirements Approvals InformationAll the other apparatus shall comprise only Appendix a Modem Specification and Interface PIN Assignments Ringer Equivalence 21/V.11 DTE Port Pin Assignments24/V.28 35/V.36 Pstn Port Cable Pin Assignments Private Line Port Cable Pin Assignments 3Com Bulletin Board Service On-line Technical ServicesCall the telephone number nearest you World Wide Web SiteSupport from Your Network Supplier Support from 3Com Returning Products for Repair Appendix B Technical Support Numerics IndexSend LED Limited Warranty 408 764-5000 3/18/96 How to Identify and Resolve Radio-TV Interference Problems