The MonitorTones packet is transmitted from a TAPI client to a TAPI server in a remote procedure call. Sending this packet enables and disables the detection of inband tones on the call. Each time a specified tone is detected, a packet is sent to the client application through TAPI.

Req_Func (4 bytes): An unsigned 32-bit integer. The identifier of the function that will be invoked on the remote server. This value MUST be set to 51.

Return Values

On completion of ClientRequest, this field contains the result of the encapsulated telephony request. A value of 0 indicates success, and a LINEERR_Constants value indicates failure. The remote server MUST complete this call synchronously.

MUST return zero if the function succeeds or an error number if an error occurs. Common return values are as follows:

Name	Value
LINEERR_INVALCALLHANDLE	0x80000018
LINEERR_OPERATIONUNAVAIL	0x80000049
LINEERR_INVALCALLSTATE	0x8000001C
LINEERR_OPERATIONFAILED	0x80000048
LINEERR_INVALTONE	0x8000003C
LINEERR_RESOURCEUNAVAIL	0x8000004B
LINEERR_NOMEM	0x80000044
LINEERR_INVALPOINTER	0x80000035

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

hCall (4 bytes): An HCALL. The handle to the call on whose voice channel tones are to be monitored. The call state of hCall can be any state except idle. One way of obtaining a valid hCall is by sending the MakeCall packet. Also a valid hCall can be obtained from LINE_CALLSTATE packet sent by the remote server.

lpToneList (4 bytes): An unsigned 32-bit integer. The offset, in bytes, in the VarData field. Contains a list of tones to be monitored of type LINEMONITORTONE.

dwNumEntries (4 bytes): An unsigned 32-bit integer. This value is equal to the number of entries in lpToneList multiplied by size of LINEMONITORTONE. The dwNumEntries parameter is ignored if lpToneList is -1(0xFFFFFFFF). TAPI does not validate this parameter when this function is called.

dwToneListID (4 bytes): An unsigned 32-bit integer. The unique identifier for this tone list.

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.

Reserved8 (4 bytes): An unsigned 32-bit integer. This field is used for padding and MUST be ignored on receipt. It can be any value.

Reserved9 (4 bytes): An unsigned 32-bit integer. This field is used for padding and MUST be ignored on receipt. It can be any value.

Reserved10 (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 (20 bytes): Contains a LINEMONITORTONE packet.

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