Telephony (TapiSrv) Service Defaults in Windows 7

Provides Telephony API (TAPI) support for programs that control telephony devices on the local computer and, through the LAN, on servers that are also running the service.

Default Settings

Startup type:Manual
Display name:Telephony
Service name:TapiSrv
Service type:share
Error control:normal
Object:NT AUTHORITY\NetworkService
Path:%SystemRoot%\System32\svchost.exe -k NetworkService
Registry key:HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\TapiSrv
  • SeAuditPrivilege
  • SeChangeNotifyPrivilege
  • SeCreateGlobalPrivilege
  • SeImpersonatePrivilege
  • SeIncreaseQuotaPrivilege
  • SeAssignPrimaryTokenPrivilege

Default Behavior

Telephony is a Win32 service. In Windows 7 it won't be started if the user doesn't start it. When the Telephony service is started, it is running as NT AUTHORITY\NetworkService in a shared process of svchost.exe. Other system components, such as drivers and services, may run in the same process. If Telephony fails to start, Windows 7 attempts to write the failure details into Event Log. Then Windows 7 startup should proceed and the user should be notified that the TapiSrv service is not running because of the error.


Telephony is unable to start, if at least one of the following services is stopped or disabled:

If Telephony is stopped, the following services cannot start:

Restore Default Startup Configuration for Telephony

Before you begin doing this, make sure that all the services on which Telephony depends are configured by default and function properly. See the list of dependencies above.

1. Run the Command Prompt as an administrator.

2. Copy the command below, paste it into the command window and press ENTER:

sc config TapiSrv start= demand

3. Close the command window and restart the computer.

The TapiSrv service is using the tapisrv.dll file that is located in the %WinDir%\System32 folder. If the file is changed, damaged or deleted, you can restore its original version from Windows 7 installation media.