Evaluating Symptoms and Solutions 129

Table 6 Symptoms, Causes, and Solutions

Symptom

Possible Cause

Solution

You are using only one telephone

If you are only using one telephone line with your LAN

line with the LAN modem, and it

Modem, it must be connected to Line 1. In this case,

is connected to the Line 2 port.

make sure that you connect the telephone line to the

 

port labeled “Line 1” on the LAN Modem’s back panel.

MODEM CD LEDs do not remain green.

A connection has been established (CD LED remains lit), but data cannot be sent.

Cannot send faxes with the Virtual Fax Modem

Outgoing calls have been disabled.

The user name and/or password for this service provider may not be entered properly.

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

Fax application does not support Class 2.0 faxes, or is not set to use Class 2.0 faxing.

Make sure that outgoing calls are enabled. Refer to “Changing Data Call Parameters” in Chapter 7 for more information.

Make sure that the user name and password for this service provider are entered accurately on the Service Provider page.

Make sure that the local and remote data applications have communications capability and are properly configured.

Make sure you are using a Fax application that supports and is set to use Class 2.0 faxing (Class 2 and Class 2.0 are not the same). An example of a Fax application that supports Class 2.0 is provided on the 3Com Companion Programs CD ROM, or may be downloaded from the LAN Modem Utilities Web site (http://www.3com.com/support/docs/util.html).

Calls continue to reconnect, or calls do not time out and disconnect.

Some application software does not work properly

Unable to connect at 56Kbps

An application or LAN device is sending IP packets.

The application may have an embedded IP address, which causes a problem when NAT is enabled on the LAN Modem.

56K may not be supported by your remote server

FCC limitations

Poor line conditions

Enable NetBIOS filtering. Refer to Chapter 7, “NetBIOS Filtering” for more information:

Make sure that the Dual 56K LAN Modem’s data call timeout value is not set to 0. Check the timeout values configured for the LAN Modem, as explained in “Changing Data Call Parameters,” Chapter 7.

Using the Manual Calling page, drop the call, wait for the spurious call to be re-connected, and then check Current Call Information from the Statistics page for Reason for call coming up.

If the situation persists, disconnect each attached LAN device to locate the source of the IP packet generation.

Or, you can turn off Automatic Call Initiation, located on each service provider parameter page. In this case, all outgoing calls can be made via the Manual Call Control page.

If you have a static network, disable NAT and try the application again.

A complete list of applications tested for use with the LAN Modem is located at

http://www.3com.com/support/docs/lanmodem/

documentation/interop.html

In order to take advantage of 56K-based analog connections, your remote server (such as an ISP) must support 56K technology. To locate a 56K-enabled ISP in your area, visit http://www.3com.com/56K.

Current FCC rules restrict the power output of a Service Provider’s modems, limiting download speeds to 53Kbps.

Check with your telephone company to ensure that maximum clarity exists for your telephone lines.

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3Com Dual 56K manual Documentation/interop.html