Microsoft KB Archive/892895

= The telephony client cannot communicate with the telephony server in Windows XP Service Pack 2 =

PSS ID Number: 892895

Article Last Modified on 2/28/2005

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The information in this article applies to:


 * Microsoft Windows XP Home Edition
 * Microsoft Windows XP Professional

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SYMPTOMS
When you try to use the telephony client in Microsoft Windows XP Service Pack 2 (SP2), the telephony client cannot communicate with the telephony server.



CAUSE
This issue occurs when you use connection-oriented callbacks to install the telephony client on a Windows XP SP2-based computer.

For example, this issue occurs when you run the following command to install the telephony client:

tcmsetup /r /x /c

Note In this command line, the /x switch represents the connection-oriented callbacks.

This problem occurs because the remote telephony service provider (TSP), such as the Remote TSP (Remotesp.tsp) component, uses a remote procedure call (RPC) for communication between the telephony client and the telephony server. By default, Windows Firewall in Windows XP SP2 blocks the RPC port.



RESOLUTION
To resolve this problem, configure Windows Firewall to enable communication between the telephony client and the telephony server.

To do this, follow these steps:
 * 1) Click Start, click Run, type firewall.cpl in the Open box, and then click OK.
 * 2) In the Windows Firewall dialog box, click the Exceptions tab, and then click Add Port.
 * 3) In the Name box, type Remotesp, and then type 251 in the Port number box. Leave the TCP option selected.
 * 4) Click OK to close the Add a Port dialog box, and then click OK to close the Windows Firewall dialog box.

Note If the telephony client still cannot communicate with the telephony server, either restart your computer and try again or contact your TSP.



STATUS
This behavior is by design.

Keywords: kbprb KB892895

Technology: kbWinXPHome kbWinXPHomeSearch kbWinXPPro kbWinXPProSearch kbWinXPSearch

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