Nortel Networks 56K manual Troubleshooting, Modem does not respond to AT commands

Page 14

Troubleshooting

This appendix contains information that will help you to solve some of the common problems you might encounter, while using this 56Kbps USB modem.

Modem does not respond to AT commands

There may be a COM port/IRQ conflict. Reconfigure the modem COM port address and IRQ line.

Make sure that you have set the correct COM port and IRQ in the communications software.

Make sure the system is in Terminal mode of your communications software.

Modem cannot dial and “NO DIALTONE” message appears on the monitor

Check the phone cord connection. Make sure that the jack on the modem labeled Line is connected to an analog phone wall jack.

The modem cannot recognize the dial tone. This is typical in some corporate PBXs. Use the ATX1 command in your setup string to enable Blind Dial.

The modem does not answer an incoming call

Auto-answer function is disabled. Enable the function through software or by sending the ATS0=1 command to your modem in terminal mode.

The modem disconnects while online

This may be caused by line interference. Retry the connection by dialing the numbers several times.

An incoming call may have broken the connection if the Call-waiting feature is enabled. Disable Call-waiting and try again.

Garbage characters display on the monitor

Set your modem to the same word length, parity, and stop bits as the remote modem.

Make sure that your software and modem are set to the same flow control setting.

The software may not be set for correct terminal emulation.

Configure the software to correct type. ANSI terminal emulation is the most commonly used.

Type the AT&F command to load the factory default settings

NetComm Roadster Series 56K USB Modem

�m�5�60 7

14

www.netcomm.com.au

Image 14
Contents User Guide Table of Contents PrefaceIntroduction General Description Features & SpecificationsIntroduction Data ModemSystem Requirements Package IncludesHardware Setup Installing the 56Kbps USB ModemConfigure the Modem on Win9X/WinME/Win2000/WinXP/Vista/7 Commands Commands Basic AT Command GuideDdial string-Dial Bvalue-Communication Standard SettingCvalue-Carrier Control Ivalue-Request ID InformationMvalue-Speaker Control Ovalue-Return to On-Line Data ModeHvalue-Hook Control Nvalue-Modulation HandshakeQvalue Result Code Control Zvalue Reset and Recall Stored ProfileSelect Pulse Dialing Select Tone DialingTroubleshooting Modem does not answer an incoming call TroubleshootingModem does not respond to AT commands Modem disconnects while onlineAppendix RJ11 connector and cable Appendix a Cable ConnectionsCustomer Information Appendix B Registering your NetComm ProductLegal & Regulatory Information Product Warranty GNU General Public LicenseLimitations of Warranty Product Warranty Technical Support

56K specifications

Nortel Networks, a leading telecommunications equipment manufacturer, played a crucial role in the development of modem technology during the late 1990s and early 2000s. Among its most notable contributions was the Nortel Networks 56K modem. Introduced at a time when dial-up internet access was the norm, the 56K modem represented a significant leap forward in data transmission speeds for both residential users and businesses alike.

One of the main features of the Nortel Networks 56K modem was its ability to achieve faster data rates compared to its predecessors. While earlier modems operated at speeds of 28.8 Kbps or 33.6 Kbps, the Nortel 56K modem could theoretically reach connection speeds of 56 Kbps under optimal conditions. This enhancement was made possible through the implementation of newer modulation techniques, such as Pulse Amplitude Modulation (PAM), which allowed for more efficient data transmission over standard telephone lines.

The 56K modem was designed to work effectively over existing analog phone lines, which was a crucial characteristic during that time. It could connect directly to the existing Public Switched Telephone Network (PSTN), making it accessible for millions of users without the need for any special infrastructure upgrades. This meant that both home users and businesses could benefit from the increased speed without significant investment.

Another notable feature was the robustness of the Nortel 56K modem's error correction capabilities. Technologies such as V.42 and V.42bis compression were integrated to enhance data integrity. These error-correcting protocols stitched together fragmented data packets, thereby ensuring reliable and stable connections, even over less-than-perfect phone lines. This reliability was vital for users who relied on modems for email, file transfers, and browsing the web.

In terms of compatibility, the Nortel Networks 56K modem was designed to work seamlessly with various operating systems, ensuring that users could connect to the internet regardless of their hardware setup. The plug-and-play capability made installation straightforward, allowing users to start browsing the web quickly.

While the Nortel Networks 56K modem was eventually eclipsed by DSL and broadband technologies that offered even higher speeds, it played an instrumental role in transitioning users from slower modems to a more connected world. The impact of Nortel's 56K modem can still be felt today, as it laid the groundwork for future innovations in digital communications and paved the way for the fast-paced internet landscape we experience now.