The supplementary line service functions are listed by category in the following topics. A function is identified as asynchronous if it will indicate completion in a REPLY message to the application. If the function always returns its result to the application immediately, the function is considered synchronous.
| lineSetCallParams | Requests a change in the call parameters of an existing call. Synchronous. |
| lineMonitorMedia | Enables or disables media mode notification on a specified call. Synchronous. |
| lineMonitorDigits | Enables or disables digit detection notification on a specified call. Synchronous. |
| lineGatherDigits | Performs the buffered gathering of digits on a call. Synchronous. |
| lineMonitorTones | Specifies which tones to detect on a specified call. Synchronous. |
| lineSetMediaControl | Sets up a call's media stream for media control. Synchronous. |
| lineSetMediaMode | Sets the media mode(s) of the specified call in its LINECALLINFO structure. Synchronous. |
| lineGenerateDigits | Generates inband digits on a call. Synchronous. |
| lineGenerateTone | Generates a given set of tones inband on a call. Synchronous. |
| lineAccept | Accepts an offered call and starts alerting both caller (ringback) and called party (ring). Asynchronous. |
| lineRedirect | Redirects an offering call to another address. Asynchronous. |
| lineDrop | Disconnects a call, or abandons a call attempt in progress. Asynchronous. |
| lineHold | Places the specified call on hard hold. Asynchronous. |
| lineUnhold | Retrieves a held call. Asynchronous. |
| lineSecureCall | Secures an existing call from interference by other events such as call-waiting beeps on data connections. Asynchronous. |
| lineSetupTransfer | Prepares a specified call for transfer to another address. Asynchronous. |
| lineCompleteTransfer | Transfers a call that was set up for transfer to another call, or enters a three-way conference. Asynchronous. |
| lineBlindTransfer | Transfers a call to another party. Asynchronous. |
| lineSwapHold | Swaps the active call with the call currently on consultation hold. Asynchronous. |
| lineSetupConference | Prepares a given call for the addition of another party. Asynchronous. |
| linePrepareAddToConference | Prepares to add a party to an existing conference call by placing the conference call in a hold state and creating a consultation call that can be added later to the conference call. Asynchronous. |
| lineAddToConference | Adds a consultation call to an existing conference call. Asynchronous. |
| lineRemoveFromConference | Removes a party from a conference call. Asynchronous. |
| linePark | Parks a given call at another address. Asynchronous. |
| lineUnpark | Retrieves a parked call. Asynchronous. |
| lineForward | Sets or cancels call forwarding requests. Asynchronous. |
| linePickup | Picks up a call alerting at a specified destination address and returns a call handle for the picked-up call (linePickup can also be used for call waiting). Asynchronous. |
| lineReleaseUserUserInfo | Releases user-user information, permitting the system to overwrite this storage with new information. Asynchronous. Version 0x00010004. |
| lineSendUserUserInfo | Sends user-user information to the remote party on the specified call. Asynchronous. |
| lineCompleteCall | Places a call completion request. Asynchronous. |
| lineUncompleteCall | Cancels a call completion request. Asynchronous. |
| lineSetTerminal | Specifies the terminal device to which the specified line, address events, or call media stream events are routed. Asynchronous. |
| lineGetAppPriority | Retrieves handoff and/or Assisted Telephony priority information for an application. Synchronous. Version 0x00010004. |
| lineSetAppPriority | Sets the handoff and/or Assisted Telephony priority for an application. Synchronous. Version 0x00010004. |
| lineAddProvider | Installs a telephony service provider. Synchronous. Version 0x00010004. |
| lineConfigProvider | Displays configuration dialog box of a service provider. Synchronous. Version 0x00010004. |
| lineRemoveProvider | Removes an existing telephony service provider. Synchronous. Version 0x00010004. |
| lineGetProviderList | Retrieves a list of installed service providers. Synchronous. Version 0x00010004. |
| lineAgentSpecific | Allows the application to access proprietary handler-specific functions of the agent handler associated with the address. Asynchronous. Version 0x00020000. |
| lineGetAgentActivityList | Obtains the list of activities from which an application selects the functions an agent is performing. Asynchronous. Version 0x00020000. |
| lineGetAgentCaps | Obtains the agent-related capabilities supported on the specified line device. Asynchronous. Version 0x00020000. |
| lineGetAgentGroupList | Obtains the list of agent groups into which an agent can log into on the automatic call distributor. Asynchronous. Version 0x00020000. |
| lineGetAgentStatus | Obtains the agent-related status on the specified address. Asynchronous. Version 0x00020000. |
| lineSetAgentActivity | Sets the agent activity code associated with a particular address. Asynchronous. Version 0x00020000. |
| lineSetAgentGroup | Sets the agent groups that the agent is logged into on a particular address. Asynchronous. Version 0x00020000. |
| lineSetAgentState | Sets the agent state associated with a particular address. Asynchronous. Version 0x00020000. |
| lineProxyMessage | Used by a registered proxy request handler to generate TAPI messages. Synchronous. Version 0x00020000. |
| lineProxyResponse | Indicates completion of a proxy request by a registered proxy handler. Synchronous. Version 0x00020000. |
| lineSetCallQualityOfService | Requests a change of the quality of service parameters for an existing call. Asynchronous. Version 0x00020000. |
| lineSetCallData | Sets the CallData member of the LINECALLINFO structure. Asynchronous. Version 0x00020000. |
| lineSetCallTreatment | Sets the sounds that the user hears when a call is unanswered or on hold. Asynchronous. Version 0x00020000. lineSetLineDevStatus |
| Sets the line device status. Asynchronous. Version 0x00020000. |