3Com 3C892 manual To Use two B Channels

Evaluating Symptoms and Solutions 97

Table 6 Symptoms, Causes, and Solutions

Symptom Possible Cause Solution

May be an incompatibility with the router into which you are dialing. Some remote routers split the two B channels of a Multilink

PPPcall between different routing devices, preventing the channels from being linked.

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.

A Multilink PPP call was established but did not remain connected.

When the LAN Modem is configured to Use 2 B channels and the remote end disconnects one of the 2 B channels, the LAN Modem will disconnect the now single B channel call since it’s configured to use 2 B channels.

From the ISDN LAN Modem’s home page, click Service Providers and then select the provider you were connecting to using Multilink PPP. For Bandwidth Allocation, select Add second B channel as required.

A voice or data call may already	Place the Multilink PPP call when both B channels are
be connected leaving only one	available.
B channel available.

Although only one data call is connected, another voice or data call cannot be placed.

Caller ID date and time are not accurate.

The connected call may be configured to always use two

B channels, leaving no bandwidth available for another call.

Check the bandwidth allocation setting for that service provider. Refer to “Editing Service Provider Profiles” in Chapter 6 for details.

Connect a workstation that has the correct time to the ISDN LAN Modem and then turn the LAN Modem power off and then on again. Once it is powered up, launch your web browser and go to the LAN Modem's main page at http://3Com.oc.lanmodem/

Cannot place a call over the LAN Modem's phone port using a Sportster PC Card modem.

Cannot place or receive two simultaneous voice calls.

After placing a Multilink PPP call, you lift the handset of a telephone to place a call and do not hear a dial tone.

Modem mistakes analog phone line for digital line.

Your ISDN line may not support simultaneous voice and data on both B channels.

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.

Add the following command to the Sportster modem init string: AT ~~L0.

Check with your ISDN line provider to determine whether or not your ISDN line supports simultaneous voice and data on both B channels.

For a Lucent 5ESS switch, your ISDN line must have Max B Channel Limit=2 for simultaneous voice and data.

For a Siemens switch, your ISDN line must have Number of B Channels Per Call Type Per Office Equipment Directory Number (NBCCTOEDN) =2.

Hang up the handset, wait a few seconds, and then try again.

Not receiving message	Message Service box is not	From the ISDN LAN Modem’s main configuration page,
indication for Voice Mail or any	checked.	click ISDN Parameters. Under Supplementary Services,
voice mail messages.		check the box labeled Message Service.
Cannot hear dial tone when	Bandwidth Allocation may be set	Go to the appropriate Service Providers page and
attempting to place a call using	to Use two B Channels.	change the Bandwidth Allocations setting to Add
an ISDN LAN Modem phone		second B channel as required.
port.
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