WINDOWS 1002000 PROFESSIONAL RESOURCE KIT [Electronic resources] نسخه متنی

Troubleshooting

The following section describes the techniques and procedures that can be used to determine and resolve problems within telephony applications and in telephony device configuration, and H.323 and multicast conferencing.

Troubleshooting Modems

The following sections detail troubleshooting procedures for analog and ISDN modems.

An analog or ISDN modem is not listed

If your modem is not on the Windows 2000 Hardware Compatibility List (HCL) or is not detected by the Install New Hardware or Install New Modem Wizards, 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 from the Action menu to reinstall the modem. If the modem is a non-Plug and Play device, reinstall the modem using Add/Remove Hardware.

Obtain an .inf (installation) file from the modem manufacturer specifically designed for Windows 2000. Follow the manufacturer's instructions for installing the modem in Windows 2000, or contact the modem manufacturer for assistance with this procedure.

Install your modem as a standard modem using the Install New Modem or Install New Hardware Wizards. This option provides basic dialing and connectivity support for the modem, although manufacturer-specific features might be unavailable.

Phone Dialer cannot dial selected modem

If you cannot use Phone Dialer (or any other application) to dial your modem, verify that Windows 2000 is able to connect to it by testing the modem. In Control Panel, open Phone and Modem Options, and then select the Modems tab, then click Properties for the modem, then select the Diagnostics tab. Click the Query Modem button 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 2000 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 (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, there is most likely a hardware or a configuration problem. 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 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 with the same number as the internal modem.

Make sure there are no other adapters or devices that are configured for the same base I/O address or IRQ as the internal modem.

Verify that the internal modem is not defective. Also, it is often a good idea to check with the vendor of your modem to see if there is a flash upgrade available for your modem.

The following sections outline common problems and solutions for conventional (non-IP) Public Switched Telephone Network (PSTN) telephony deployment.

Computer cannot find the telephony server

If the telephony server cannot be reached through 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 severs 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).

One or more client computers cannot find a line on the telephony server

If one or more client computers cannot "see" the lines of a telephony server, it might be because they are unable to be authorized for access to lines on the telephony server. When a TAPI application accesses lines on the telephony server, the user context associated with the application process is first authenticated. This means that those lines must have been configured on the server to allow access by that client. If the client cannot see lines on the telephony server, it is possible that the lines have not been configured on the server to allow access by the client. Contact the system administrator for the server.

After the lines have been configured, the new settings are not available until TAPI on the client computer restarts. The solution is to stop all client TAPI applications and restart Windows 2000 Professional. When the client applications restart, they are able to see the newly allocated lines.

An application fails to start after you have canceled the Location Information dialog box

If an application fails to start after you have canceled out of the Location Information dialog box, the problem might be that address translation required by TAPI applications has not been specified. This can be solved by using the Local Information dialog box to enter your country/region code, local area code, and pulse or tone and external line access settings.

A client cannot find a new line appearance on the server, even though the server administrator has assigned the client to the line

When you assign a currently running client to a line on the telephony server, the new settings are not available until TAPI on the client computer restarts. The solution is to stop all client TAPI applications so that TAPI shuts down. When the client applications restart, they are able to see the newly allocated lines.

Troubleshooting Conferencing Applications

Users of H.323 or multicast conferences might encounter problems connecting with other users or receiving audio or video.

Audio problems in conferencing applications

If audio problems occur in H.323 or multicast video conferences, the microphones or sound cards on the client computers might be incorrectly configured or malfunctioning.

To diagnose sound hardware on Windows 2000 Professional computers, start the Sound Recorder application by clicking Start, pointing to Programs, Accessories, Entertainment, and then clicking Sound Recorder, or 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, check if 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 through Volume Control

Click Start, point to Programs, point to Accessories, point to Entertainment, and then select Volume Control.

In the Volume Control dialog box, select Options, Properties, and then click Playback. Make sure that the Wave and Microphone check boxes are selected. You might have to scroll the window in order 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 and/or Wave sliders downward or upward as needed.

Select Options, Properties, and then click Recording. Select all of the check boxes in the window at the bottom of the dialog box. (You might have to scroll the window in order 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 is left unchecked. 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, check if the affected computers have full-duplex sound cards. Full-duplex sound cards are capable of capturing and playing 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 is unable to properly record a sample while the first instance is recording, 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. Check with the manufacturer of your sound cards to ensure that you are using the most recent Windows 2000 drivers. Also, replace the microphones and sound cards on affected computers and attempt these tests again.

Eliminating audio echo

Audio echo is a common problem with audio conferencing systems. Echo can originate in the local audio loop-back that happens when a user's microphone picks up sounds from their 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.

One of the easiest ways to completely eliminate audio echo is to use audio headsets. These work by eliminating 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.

Video problems in conferencing applications

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 see by all of the other endpoints, the computer's video capture device might not be working properly. When using Phone Dialer, participants should be able to see their own video image whenever they participate in videoconferences. If this is not the case, run the camera troubleshooter included in Windows 2000 Help.

Audio and video problems in multicast conferences can also be caused by multicast issues. The following section describes how to diagnose these problems using the MCAST tool included in the Microsoft® Windows® 2000 Professional Resource Kit.

Verifying network is configured for multicast packets

If you are uncertain whether your network is configured to send and receive multicast packets, use the MCAST diagnostic tool. MCAST can send and receive multicast packets, helping you to determine which parts of your network are enabled for transmission of IP multicast packets. MCAST is supplied with the Microsoft® Windows® 2000 Professional Resource Kit. Install MCAST on the computer in question.

You can use MCAST in send mode to set up multicast sources at different locations on your network, and in receive mode to determine the locations at which multicast traffic from these sources is being received.

The following example shows MCAST being run as a multicast sender, on a Windows 2000 Professional–based computer:

MCAST /SEND /INTF:172.31.253.55 /GRPS:230.1.1.1 /INTVL:1000
/NUMPKTS:3600

MCAST will start sending multicast packets from the IP address 172.31.255.255 to the multicast group IP address 230.1.1.1 at the rate of 1 packet per every 1000 milliseconds. A total of 3600 packets will be sent over a one-hour period.

To run MCAST as a multicast receiver, use a command-line as follows:

MCAST /RECV /INTF: 172.31.255.255/GRPS:230.1.1.1

MCAST will start listening for multicast packets on the IP address 172.31.255.255 for the multicast group IP address 230.1.1.1. Received packets are displayed on the screen:

Started.... Waiting to receive packets...
Received [1]: [GOOD] SRC- 172.31.253.55 GRP- 230.1.1.1    TTL- 5 Len-
256
Received [2]: [GOOD] SRC- 172.31.253.55 GRP- 230.1.1.1    TTL- 5 Len-
256
Received [3]: [GOOD] SRC- 172.31.253.55 GRP- 230.1.1.1    TTL- 5 Len-
256
Received [4]: [GOOD] SRC- 172.31.253.55 GRP- 230.1.1.1    TTL- 5 Len-
256
Received [5]: [GOOD] SRC- 172.31.253.55 GRP- 230.1.1.1    TTL- 5 Len-
256

Unable to publish multicast conference invitations

If you are unable to publish multicast conference invitations, confirm with your network administrator that the Site Server ILS Service is available at your site. The Site Server ILS Service is an essential component of TAPI IP Multicast Conferencing. This server represents the meeting place where conference creators and participants go through their client software application to find the information they need to participate in a conference.

Windows 2000 Phone Dialer cannot see ILS

The Windows 2000 Phone Dialer application must know the location of the Site Server ILS Service to provide conference creation and joining facilities.

The Phone Dialer application can locate this information in Active Directory^™ directory service if the following conditions are fulfilled:

The computer running the Phone Dialer application is part of a Windows 2000 domain.

The user is logged on using a Windows 2000 domain account.

The ILS server location is published in Active Directory.

Using Active Directory in this way means that users do not need to know the location of the ILS server on their network or manually enter that information into their Phone Dialer application. This makes using IP Multicast Conferencing with Windows 2000 easier for the user.

Computer or user cannot access Active Directory

All of the components required to support TAPI Multicast Conferencing on a client computer are installed by default in Windows 2000 Professional. However, in order for a computer or a user to use TAPI Multicast Conferencing, they need to be added to a Windows 2000 domain. If computer or user accounts for Windows 2000 domain are not created, users cannot access Active Directory directory service and will need to add their ILS servers to the Phone Dialer application manually.

Troubleshooting NetMeeting

Although NetMeeting supports multi-user data conferencing, you can connect with only one other person at a time with audio or video functions. Other audio and video troubleshooting issues are also described in the following sections.

Cannot place a call in NetMeeting

If you are in a network environment that uses a proxy server and are attempting to access a Web-based directory server or to contact someone on the Internet, verify that your proxy server supports NetMeeting. If the proxy supports NetMeeting, attempt to ping the directory using its DNS name or IP address to check availability.

If a gatekeeper is used to establish calls, you might have to log on to the gatekeeper using an established alias. Contact your system administrator for details.

Some directory names are case-sensitive; verify the correct capitalization used in a directory name before attempting to place a call.

If you cannot place a call using a computer name, try using their IP address. If the IP address is unknown, ping the computer you are attempting to call, using the full DNS name of the host.

Audio problems in NetMeeting

If the audio functions of NetMeeting application have worked previously, and any changes have occurred in the sound card device driver (such as upgrading to a full-duplex driver) run the Audio Tuning Wizard again in order to reconfigure the NetMeeting audio settings. If running the Audio Tuning Wizard does not solve the problem, check the hardware and driver configuration, as described in "Troubleshooting H.323 Calls and Multicast Conferencing" earlier in this chapter.

Video problems in NetMeeting

If your video capture device fails to preview video, verify that the correct display codec is selected for your video device. Select Tools/Options from the NetMeeting menu bar, select the Video tab, then click Source to view the codec selected for the current session. select the correct codec, then close and restart NetMeeting.

If another application is using the same video device selected for your NetMeeting video conference, the video functions in NetMeeting might be disabled. Select another video device or close the other application.

If you are using the video capture functions in a dark area, some cameras cause the session to become extremely slow and unresponsive. Some video drivers provide a low-light filter option. Enable the option if available.