3Com Dual 56K User Manual page 129

Table 6 Symptoms, Causes, and Solutions
Symptom
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
Calls continue to reconnect, or
calls do not time out and
disconnect.
Some application software
does not work properly
Unable to connect at 56Kbps
Possible Cause
You are using only one telephone
line with the LAN modem, and it
is connected to the Line 2 port.
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.
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
Evaluating Symptoms and Solutions
Solution
If you are only using one telephone line with your LAN
Modem, it must be connected to Line 1. In this case,
make sure that you connect the telephone line to the
port labeled "Line 1" on the LAN Modem's back panel.
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).
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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