Microsoft Windows XP Professional Resource Kit 2003
ISBN: N/A
EAN: N/A
EAN: N/A
Year: 2005
Pages: 338
Pages: 338
You can use the following techniques and procedures to determine and resolve problems within telephony applications and in telephony device configuration, and H.323 and multicast conferencing.
The following sections detail troubleshooting procedures for analog and ISDN modems.
If your modem is not on the Windows XP Professional Hardware Compatibility List (HCL) or is not detected by the Add Hardware Wizard, use one of the following procedures to install it:
Check the modem. If it is an external modem, make sure it is turned on, and all cables are tightly connected. If the modem is internal, verify that it is properly installed.
If the modem is a Plug and Play device, open Device Manager in Control Panel and select Scan for hardware changes on the Action menu to reinstall the modem. To open Device Manager, open Control Panel, and then double-click System. Click the Hardware tab, and then click Device Manager. If the modem is not a Plug and Play device, reinstall the modem using Add Hardware.
Obtain an .inf (installation) file from the modem manufacturer specifically for Windows XP Professional. Follow the manufacturer s instructions for installing the modem in Windows XP Professional, or contact the modem manufacturer for assistance.
Install your modem as a standard modem by using the Add Hardware Wizard. This option provides basic dialing and connectivity support for the modem, although manufacturer-specific features might be unavailable.
If you cannot use an application to dial your modem, test the modem to verify that Windows XP Professional can connect to it. In the Phone and Modem Options dialog box, select the Modems tab, click Properties for the modem you want, and then select the Diagnostics tab. Click Query Modem to send a set of AT commands to the modem. If the modem response is not displayed in the Response area, then perform the following steps to diagnose the problem:
If an external modem is experiencing problems, make sure that the serial cable connection between the computer and the modem is secure and that the cable is not broken or frayed.
Verify that Windows XP Professional recognizes your COM ports by displaying Device Manager. Verify that the COM port is not experiencing a hardware or resource problem (identified by an exclamation point icon next to the device listing) or has been disabled (identified by the international No symbol). If the connected port is listed without any additional icons, the COM port is recognized and available.
If the COM port is disabled in Device Manager, a hardware or a configuration problem is likely. Use the following steps to troubleshoot the problem for an external modem:
Verify that the port is not disabled in the BIOS (also called the CMOS) setup of the computer. Refer to the documentation for your computer to obtain information about configuring options in the BIOS setup.
Make sure there are no other adapters or devices that are configured for the same base I/O address or interrupt request (IRQ) as the COM port to which the modem is attached.
Verify that the serial port is not defective. If the modem and any other serial devices fail on the COM port but work on other COM ports, and you have verified the two steps above, the serial port might be defective.
If the modem experiencing problems is internal, perform the following steps to diagnose and resolve the problem:
If the internal modem is not Plug and Play compatible, it might use jumpers to specify the COM port. Make sure the jumpers on the modem are configured properly. There might or might not be jumpers that allow you to set the base I/O address and IRQ to be used by the modem as well. Verify that they are properly set. Some modems use a configuration application to change these settings.
If the modem is configured for a COM port number that is assigned to a COM port on the motherboard or a serial card (physical port), you must either set the modem to use a different COM port, or use the BIOS setup to disable the COM port that has the same number as the internal modem.
Make sure that no other adapters or devices are configured for the same base I/O address or IRQ as the internal modem.
Verify that the internal modem is not defective. Also, check with the vendor of your modem to see if there is an upgrade available for your modem.
The following sections outline common problems and solutions for conventional (non-IP) PSTN telephony deployment.
If the telephony server cannot be reached by means of the network, for example, a user cannot ping the telephony server, it is possible that:
The telephony server is not available or has not been correctly set up. Contact the administrator of the telephony server.
The Tcmsetup tool has not been run. Run the Tcmsetup tool with the /c parameter to specify the correct servers.
The Tcmsetup tool has been run, but an incorrect telephony server was specified. Run the Tcmsetup tool with the /c parameter to specify the correct servers.
The Tcmsetup tool has been run multiple times, overwriting the original telephony configuration. Run the Tcmsetup tool with the /c parameter, listing all telephony servers in the single command.
The Tcmsetup tool has been run with the /d (delete) parameter. Run the tcmsetup tool with the /c parameter to enable telephony services and to specify the correct server(s).
If one or more client computers cannot find the lines for a telephony server, it might be because they cannot be authorized for access to lines on the telephony server. When a TAPI application first accesses lines on the telephony server, the user context associated with the application process is authenticated. This means that those lines must have been configured on the server to allow access by that client. Contact the system administrator for the server.
After the lines have been configured, the new settings are not available until TAPI restarts on the client. Stop all client TAPI applications and restart Windows XP Professional. When the client applications restart, they can find the newly assigned lines.
If an application fails to start after you have canceled the Location Information dialog box, the problem might be that address translation required by TAPI applications has not been specified. Use the Location Information dialog box to enter your country/region code, local area code, and pulse or tone and external line access settings.
When you assign a currently running client to a line on the telephony server, the new settings are not available until TAPI restarts on the client. Stop all client TAPI applications so that TAPI shuts down. When the client applications restart, they can find the newly assigned lines.
Users of H.323 or multicast conferencing might encounter problems connecting with other users or receiving audio or video.
If audio problems occur in H.323 or multicast video conferences, the microphones or sound cards on the clients might be incorrectly configured or malfunctioning.
To diagnose sound hardware on Windows XP Professional based computers, start the Sound Recorder application. In Accessories, point to Entertainment, and then click Sound Recorder. You can also open Sound Recorder by typing sndrec32 at the command prompt. Make a recording of your own voice using Sound Recorder, and then play it back. If there is no sound, make sure that the microphone is properly plugged in.
If the Sound Recorder test works properly but you continue to have audio problems, verify the sound settings using Volume Control.
To verify sound settings by using Volume Control
In Accessories, point to Entertainment, and then click Volume Control.
In the Options menu, click Properties, and then click Playback. Make sure that the Wave and Microphone check boxes are selected. You might have to scroll the list to see these settings.
Click OK.
Select the Mute check box in the Microphone column if it is not checked. This prevents speech from being echoed locally (played back on the speaker s computer).
If the voices of all other conference participants are too loud or too quiet, adjust the Volume Control or Wave sliders downward or upward as needed.
On the Options menu, click Properties, and then click Recording. Select all of the check boxes in the list at the bottom of the dialog box. You might have to scroll the list to see these settings.
Click OK.
Select the Mute check boxes in all of the columns except for the Microphone column if they are not already checked. Make sure that the Mute check box in the Microphone column is not selected. This allows your speech to be sent to the conference, but prevents other sounds, including those of other conference participants, from being transmitted from your computer.
If other conference participants are dissatisfied with the level of sound, adjust the Microphone slider downward or upward as needed.
| Note | A single incorrectly configured computer can cause audio problems or echoes for all other conference participants. |
If you continue to encounter audio problems after adjusting the sound settings, make sure that the affected computers have full-duplex sound cards. Full-duplex sound cards can capture and play audio simultaneously, while half-duplex sound cards can only do one at a time. Most modern sound cards are full-duplex, but many older sound cards are only half-duplex.
To check if the sound card on your computer supports full-duplex audio, start Sound Recorder and record a speech sample for approximately 30 seconds. After this is complete, open a second instance of Sound Recorder. Play the sample you recorded using the first instance of Sound Recorder, and while this is playing, attempt to record a sample using the second instance of Sound Recorder. If the second instance of Sound Recorder cannot record a sample while the first instance is playing, the sound card does not support full-duplex audio, and thus does not work with TAPI.
If sound is distorted or otherwise continues to malfunction after you attempt the above procedures, there is most likely a problem with the microphone, sound card hardware, or sound card driver. Contact the manufacturer of your sound cards to ensure that you have the most recent Windows XP Professional drivers. Also, replace the microphones and sound cards on affected computers and attempt these tests again.
Audio echo is a common problem with audio conferencing systems. Audio echo is often more detectable when using a microphone and speakers, as opposed to using a headset, which has an integrated microphone and speakers. For example, echo can originate in the local audio loopback that happens when a user s microphone picks up sounds from the user s speakers and transmits it back to the other participants. Normal conversation can become impossible for other participants in the conference when sensitive microphones are used, speaker level is high, or the microphone and speakers are placed in close proximity to each other.
TAPI 3.1 applications written to use the acoustic echo cancellation capabilities of either the H.323 Service Provider or Multicast Conference Service Provider allow for the elimination of acoustic echo when using a microphone and speakers.
Another way to completely eliminate audio echo is to use audio headsets. These eliminate the possibility of a user s microphone picking up sound that is being received from other conference participants.
A more expensive solution is to use special microphones with built-in echo-canceling capabilities. These microphones detect and cancel out echo. The main advantage to these is that users do not have to wear headsets. Echo-canceling microphones are also a necessity for conference rooms because using headphones is not a practical solution.
If the video image of an H.323 conference participant cannot be seen by the other party, or if the image of a multicast conference participant cannot be seen by all of the other endpoints, the computer s video capture device might not be working properly. See the camera troubleshooter in Windows XP Professional Help and Support Center.
If you cannot publish multicast conference invitations, confirm with your network administrator that a Windows directory service is available at your site. The directory service provides the ability to publish IP multicast conferences.