3Com DIGITAL MODEM manual Troubleshooting

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3-4 CHAPTER 3: TROUBLESHOOTING

■If you are unable to establish a data call, carefully monitor the B-1 and B-2 LEDs while attempting a data call. The B-1 and B-2 LEDs flash green during the data call establishment phase. They then remain continuously green once the data connection is established.

■If neither of the B-1 or B-2 LEDs flashes green, check to make sure that your computer is turned on and operational, that your 3Com Impact digital modem cable is properly connected and not damaged, and that your application software has sent an AT dial command in the proper format.

Depending upon the location of the destination call you are dialing, there may be an incompatible local or toll telephone company. Though this is less likely, if you suspect a telephone company problem in dialing local or toll data connections, contact your local telephone company and have it verify that you can dial a data call to the destination telephone number.

7If you are able to establish a data call, in which the B-1 or B-2 green LED remains lit and you receive a CONNECT message at your application software, but you are unable to send data, then it is possible that:

■There is a difference in the local and remote B channel data rates.

■There is a mismatch in the data communications protocols.

■There is an interoperability mismatch between the local and remote applications.

■Make sure that the local and remote data applications have communication capability and are properly configured. Once you have verified that communication capability exists, make sure that the B channel call data rate is the same as the remote destination call data rate. The default B channel data rate used by the digital modem is 56 Kbps. Under some circumstances, the data rate may be increased to 64 Kbps at both ends of the connection.

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Contents Isdn External Digital Modem User Guide Member of the 3Com Impact product family3Com Corporation 5400 Bayfront Plaza Santa Clara, California Contents QuickSelect Support from 3Com C-4 Returning Products for Repair C-4Figures Tables About this Guide How to Use This GuideIntroduction Conventions Introduction Introduction 3Com Impact Digital Modem Features 3Com Impact digital modem provides the followingVoice Capabilities Data CapabilitiesSimultaneous Data and Voice Capabilities 3Com Impact Digital Modem Package Contents Isdn Digital Line Configuration Requirements 3ComA * J6Computer System Requirements AT&T 5ESSEwsd ISDN-1IBM PC or Compatible Requirements Apple Macintosh RequirementsSignal Ground GND Clear to Send CTS From digital modem Ring Indicator RICabling Requirements DTRInstalling Configuring Digital Modem Back Panel Power Switch and ConnectorsLED Installing the 3Com Impact Digital Modem Installing the Digital Modem in an IBM-compatible PCInstalling the Digital Modem in an Apple Macintosh Computer Installing the 3Com Impact Digital Modem Configuring the 3Com Impact Digital Modem Select Run from the File menu. In the Run dialog box, type Configuration for IBM PC or Compatible ComputerCOM port to which the digital modem is connected Installing and Configuring the Digital Modem Registers Installing and Configuring the Digital Modem Install Installing and Configuring the Digital Modem Configuration for Apple Macintosh Computer Installing and Configuring the Digital Modem Placing Isdn Data Calls Placing and Receiving CallsMultilink PPP Calls With Dynamic Bandwidth Allocation Installing and Configuring the Digital Modem Using the Phone Out Port Using Communications Software to Place CallsIncoming circuit-switched data calls from other Placing Analog Modem CallsPlacing Calls Using the Phone Out Port Receiving Calls Using the Phone Out PortT1 access lines Protocol SupportAsync-Sync PPP Conversion QuickSelectTroubleshooting Troubleshooting TipsTroubleshooting Monitor the B-1 and B-2 LEDs Troubleshooting If problems persist, refer to Appendix C,Technical Support Downloading Firmware to Your External Digital ModemClick the Tools button Firmware and Tests buttons appear Click the Firmware button Firmware dialog box appearsClick OK Overview AT Command SETAT gets the attention of your 3Com Impact digital modem Type AT Command Set for the 3Com Impact Digital Modem AT Commands REGISTERS, and Result CodesTable B-1 summarizes the AT command set SN? SN=Settings AT \S Commands\T0 disables inactivity timer default Initial configuration setAT Command Set for Internal Analog Fax Modem ATC1Results of commands Received line signal levelNon-error corrected mode only Flow control Enable MNP mode Stream default BlockMode to be negotiated in a Direct MNP extended servicesEnable inhibits MNP extended Answer mode detection phaseRemote S Registers Isdn PPP Magic-Number Block Service providerS83 Digital Modem Result Codes Table B-4 lists the 3Com Impact digital modem result codesOn-line Technical Services 3Com Bulletin Board Service3ComFacts Automated Fax Service World Wide Web SiteAsk3Com on CompuServe To use Ask3Com Log on to CompuServeSupport from Your Network Supplier Country Fax Number Hong Kong 852 537Country Fax Number Italy 1678 Norway 800 Sweden 020 0800Support from 3Com Returning Products for RepairTo obtain an RMA number, call or fax Country Telephone Number Fax NumberLimited Warranty 3Com Corporation Bayfront Plaza Interference Handbook Canadian Notice

DIGITAL MODEM specifications

The 3Com Digital Modem represents a significant advancement in communication technology, designed to enhance data transmission over telephone lines. This modem is a part of a lineage of 3Com products that focus on delivering robust networking solutions, tailored for both personal and professional use.

One of the main features of the 3Com Digital Modem is its high-speed data transfer capabilities. With speeds reaching up to 56 Kbps, it allows users to send and receive large amounts of data quickly, which is essential for applications that require efficient data exchange. This speed ensures smoother internet browsing, quicker downloads, and more reliable connections for applications such as video conferencing and online gaming.

The modem is equipped with advanced error correction technologies, including V.42 and V.42bis protocols. These protocols help to maintain data integrity by detecting and correcting errors during transmission. This results in a more reliable connection, reducing the likelihood of dropped calls or corrupted data transfers, which can be particularly frustrating for users engaged in critical business communications.

Another notable characteristic of the 3Com Digital Modem is its compatibility with various operating systems, making it versatile for different users. It supports Windows, Mac, and various other platforms, ensuring that it can be integrated seamlessly into existing systems without the need for extensive configuration. This plug-and-play capability simplifies installation for users, allowing them to get connected quickly and efficiently.

The modem also incorporates an innovative design that facilitates improved heat dissipation, ensuring optimal performance during prolonged use. Its compact form factor makes it suitable for both home and office environments, allowing for easy setup without consuming excessive desk space.

In addition to these features, the 3Com Digital Modem boasts strong security protocols, ensuring that users' data is protected against unauthorized access while being transmitted. This is particularly important in today’s digital landscape, where data breaches and cyber threats are prevalent.

Overall, the 3Com Digital Modem combines speed, reliability, and security, making it a valuable asset for anyone looking to enhance their connectivity experience. Its robust feature set and user-friendly design cater to a broad audience, from casual users to business professionals, reflecting the evolution of modem technology in a digital-first world.
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