3Com OfficeConnect 3C892A User Manual page 102

C 9: T
96
HAPTER ROUBLESHOOTING AND
Table 9 Symptoms, Causes, and Solutions
Symptom
Some application software
doesn't work properly.
A connection has been
established (B1 or B2 green
LED remains lit) but data
cannot be sent.
Calls continue to reconnect or
calls do not timeout and
disconnect.
A Multilink PPP call cannot be
placed. Only one B channel
connects.
Although only one data call is
connected, another voice or
data call cannot be placed.
Cannot place a call over the
LAN Modem's phone port
using a Sportster PC Card
modem.
After placing a Multilink PPP
call, you lift the handset of a
telephone to place a call and
do not hear a dial tone.
(continued)
M
AINTENANCE
Possible Cause
Application may have an
embedded IP address which
causes a problem when NAT is
enabled on the ISDN LAN
Modem.
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.
An application or LAN device is
sending IP packets.
Multilink PPP may not be
configured properly.
There may not be enough traffic
to reach the threshold for adding
the second B channel.
May be an incompatibility with
the router into which you are
dialing. Some remote routers split
the two B channels of a Multilink
PPP call between different
routing devices, preventing the
channels from being linked.
A voice or data call may already
be connected leaving only one
B channel available.
The connected call may be
configured to always use two
B channels, leaving no bandwidth
available for another call.
Modem mistakes analog phone
line for digital line.
The handset was lifted to place a
call while the ISDN LAN Modem
was negotiating the Multilink PPP
call. Negotiation must be
complete before a call can be
placed.
Solution
If you have a static network, disable NAT and try using
the application again. Do not disable NAT if your
network is dynamic.
Make sure that the user name and password for this
service provider are entered accurately.
Make sure that the local and remote data applications
have communications capability and are properly
configured.
Go to Current or Last Call Statistics and check Reason
for call coming up.
Or, set the workgroup on each PC to workgroup.
Check applications to see if any are running in the
background.
Make sure that the timeout value is not set to zero.
Check the timeouts configured for the ISDN LAN
Modem as explained in "Changing Data Call
Parameters" in Chapter 6.
Refer to "Editing Service Provider
Chapter 6 for details.
If you configured bandwidth allocation for this service
provider to add the second B channel as needed, there
may not be enough traffic to reach the threshold
defined. Refer to "Changing Data Call
Chapter 6 for the threshold value and instructions on
how to change this value, if desired.
Try reconnecting your call during off peak hours. If you
are still unable to establish a Multilink PPP call, contact
your ISP to confirm that they support this feature.
Place the Multilink PPP call when both B channels are
available.
Check the bandwidth allocation setting for that service
provider. Refer to "Editing Service Provider
Chapter 6 for details.
Add the following command to the Sportster modem
init string: AT ~~L0.
Hang up the handset, wait a few seconds, and then try
again.
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