2.2.4.1.3.13 DevSpecificFeature

The DevSpecificFeature packet is transmitted from a TAPI client to a TAPI server in a remote procedure call. The function is used as an extension mechanism to enable service providers to provide access to features that are not described in other operations. The meanings of these extensions are device-specific, and taking advantage of these extensions requires TAPI or its client application to be fully aware of them.


0


1


2


3


4


5


6


7


8


9

1
0


1


2


3


4


5


6


7


8


9

2
0


1


2


3


4


5


6


7


8


9

3
0


1

Req_Func

Reserved1

dwRequestID

lpContext

hLine

dwFeature

lpParamsContext

lpParams

dwSize

Reserved2

Reserved3

Reserved4

Reserved5

Reserved6

Reserved7

VarData (variable)

...

Req_Func (4 bytes): The identifier of the function that will be invoked on the remote server. This value MUST be set to 14.

Return Values

On completion of ClientRequest, this field contains the result of the encapsulated telephony request. A nonzero request ID value indicates that the request is in progress and will complete asynchronously, and a LINEERR_Constants value indicates synchronous failure.

Returns a positive request identifier if the function will be completed asynchronously or a negative error number if an error occurs. The dwParam2 parameter of the corresponding LINE_REPLY packet is zero if the function succeeds, or it is a negative error number if an error occurs. If the client specified a nonzero value in the dwRequestID field of the packet, the same MUST be used as the value for the returned positive request identifier. Common return values are as follows:

Name

Value

LINEERR_INVALFEATURE

0x80000055

LINEERR_OPERATIONUNAVAIL

0x80000049

LINEERR_INVALLINEHANDLE

0x8000002B

LINEERR_OPERATIONFAILED

0x80000048

LINEERR_NOMEM

0x80000044

LINEERR_RESOURCEUNAVAIL

0x8000004B

Reserved1 (4 bytes): An unsigned 32-bit integer. MUST be set to zero when sent and MUST be ignored on receipt.

dwRequestID (4 bytes): An unsigned 32-bit integer. The identifier of the asynchronous request.

lpContext (4 bytes): An unsigned 32-bit integer. The opaque, client-specified value that is used by the client upon request completion; MUST be returned by the server in the request completion packet.

hLine (4 bytes): An HLINE. The handle to the line device. This field MUST have been obtained by sending the Open packet.

dwFeature (4 bytes): An unsigned 32-bit integer. The feature to invoke on the line device. This parameter MUST use PHONEBUTTONFUNCTION_Constants.

lpParamsContext (4 bytes): An unsigned 32-bit integer. The opaque, client-specified value that is used by the client upon request completion; MUST be returned by the server in the request completion packet.

lpParams (4 bytes): An unsigned 32-bit integer. The offset, in bytes, in the VarData field of a feature-dependent parameter block. The format of this parameter block is device-specific and its contents are passed by TAPI, to or from the TSP.

dwSize (4 bytes): An unsigned 32-bit integer. The size, in bytes, of the parameter block that is indicated in the lpParams field.

Reserved2 (4 bytes): An unsigned 32-bit integer. This field is used for padding and MUST be ignored on receipt. It can be any value.

Reserved3 (4 bytes): An unsigned 32-bit integer. This field is used for padding and MUST be ignored on receipt. It can be any value.

Reserved4 (4 bytes): An unsigned 32-bit integer. This field is used for padding and MUST be ignored on receipt. It can be any value.

Reserved5 (4 bytes): An unsigned 32-bit integer. This field is used for padding and MUST be ignored on receipt. It can be any value.

Reserved6 (4 bytes): An unsigned 32-bit integer. This field is used for padding and MUST be ignored on receipt. It can be any value.

Reserved7 (4 bytes): An unsigned 32-bit integer. This field is used for padding and MUST be ignored on receipt. It can be any value.

VarData (variable): Contains a feature-dependent parameter block that is indicated in the lpParams field. The format of this parameter block is device-specific and its contents are passed by TAPI, to or from the TSP.

The contents of this field MUST be DWORD-aligned, as specified in [MS-DTYP] section 2.2.9.