<div class="content"><p>The GetAddressCaps packet is transmitted from a TAPI <a href="489de77f-16d8-4c4f-939a-f795e8b42893#gt_60e0e1fa-66fe-41e1-b5e3-ceab97e53506" data-linktype="relative-path">client</a> to a TAPI <a href="489de77f-16d8-4c4f-939a-f795e8b42893#gt_434b0234-e970-4e8c-bdfa-e16a30d96703" data-linktype="relative-path">server</a> in a <a href="489de77f-16d8-4c4f-939a-f795e8b42893#gt_8a7f6700-8311-45bc-af10-82e10accd331" data-linktype="relative-path">remote procedure call</a>.
Sending this packet queries the specified address on the specified line device
to determine its telephony capabilities.</p><table>
 <tbody><tr>
  <th><p><br/>0</p></th>
  <th><p><br/>1</p></th>
  <th><p><br/>2</p></th>
  <th><p><br/>3</p></th>
  <th><p><br/>4</p></th>
  <th><p><br/>5</p></th>
  <th><p><br/>6</p></th>
  <th><p><br/>7</p></th>
  <th><p><br/>8</p></th>
  <th><p><br/>9</p></th>
  <th><p>1<br/>0</p></th>
  <th><p><br/>1</p></th>
  <th><p><br/>2</p></th>
  <th><p><br/>3</p></th>
  <th><p><br/>4</p></th>
  <th><p><br/>5</p></th>
  <th><p><br/>6</p></th>
  <th><p><br/>7</p></th>
  <th><p><br/>8</p></th>
  <th><p><br/>9</p></th>
  <th><p>2<br/>0</p></th>
  <th><p><br/>1</p></th>
  <th><p><br/>2</p></th>
  <th><p><br/>3</p></th>
  <th><p><br/>4</p></th>
  <th><p><br/>5</p></th>
  <th><p><br/>6</p></th>
  <th><p><br/>7</p></th>
  <th><p><br/>8</p></th>
  <th><p><br/>9</p></th>
  <th><p>3<br/>0</p></th>
  <th><p><br/>1</p></th>
 </tr>
 <tr>
  <td colspan="32">
  <p align="center">Req_Func</p>
  </td>
 </tr>
 <tr>
  <td colspan="32">
  <p align="center">Reserved1</p>
  </td>
 </tr>
 <tr>
  <td colspan="32">
  <p align="center">hLineApp</p>
  </td>
 </tr>
 <tr>
  <td colspan="32">
  <p align="center">dwDeviceID</p>
  </td>
 </tr>
 <tr>
  <td colspan="32">
  <p align="center">dwAddressID</p>
  </td>
 </tr>
 <tr>
  <td colspan="32">
  <p align="center">dwTSPIVersion</p>
  </td>
 </tr>
 <tr>
  <td colspan="32">
  <p align="center">dwExtVersion</p>
  </td>
 </tr>
 <tr>
  <td colspan="32">
  <p align="center">lpAddressCaps</p>
  </td>
 </tr>
 <tr>
  <td colspan="32">
  <p align="center">Reserved2</p>
  </td>
 </tr>
 <tr>
  <td colspan="32">
  <p align="center">Reserved3</p>
  </td>
 </tr>
 <tr>
  <td colspan="32">
  <p align="center">Reserved4</p>
  </td>
 </tr>
 <tr>
  <td colspan="32">
  <p align="center">Reserved5</p>
  </td>
 </tr>
 <tr>
  <td colspan="32">
  <p align="center">Reserved6</p>
  </td>
 </tr>
 <tr>
  <td colspan="32">
  <p align="center">Reserved7</p>
  </td>
 </tr>
 <tr>
  <td colspan="32">
  <p align="center">Reserved8</p>
  </td>
 </tr>
 <tr>
  <td colspan="32">
  <p align="center">VarData
  (variable)</p>
  </td>
 </tr>
 <tr>
  <td colspan="32">
  <p align="center">...</p>
  </td>
 </tr>
</tbody></table><p><b>Req_Func (4 bytes): </b>An unsigned 32-bit
integer. The identifier of the function that is invoked on the remote server.
This value MUST be set to 21.</p><dl>
<dd>
<p><b>Return Values</b></p>
</dd>
<dd>
<p>On completion of <a href="c28c36d0-579b-4e20-a100-f4e71012d5f8" data-linktype="relative-path">ClientRequest</a>, this field
contains the result of the encapsulated telephony request. A value of 0
indicates success, and a <a href="e0e8af90-24f1-4dbc-8d4e-01b8e4e7cb53" data-linktype="relative-path">LINEERR_Constants</a>
value indicates failure. The remote server MUST complete this call synchronously.</p>
</dd>
<dd>
<p>MUST return zero, if the function succeeds; or an
error number, if an error occurs. </p>
</dd></dl><p><b>Reserved1 (4 bytes): </b>An unsigned 32-bit
integer. MUST be set to zero when sent and MUST be ignored on receipt. </p><p><b>hLineApp (4 bytes): </b>An <a href="c12b4793-3220-4f9e-aa86-8edd3e7020d4" data-linktype="relative-path">HLINEAPP</a>. A handle to the
application&#39;s registration with TAPI. This field MUST have been obtained by
sending the <a href="9d8eb7cd-3245-4e44-97e0-42f7b89c9424" data-linktype="relative-path">Initialize</a>
packet.</p><p><b>dwDeviceID (4 bytes): </b>An unsigned 32-bit
integer. The line device that contains the address to be queried. A valid value
of dwDeviceID is in the range 0 to dwNumDevs – 1. The client obtains dwNumDevs
by sending a Initialize packet to the remote server.</p><p><b>dwAddressID (4 bytes): </b>An unsigned 32-bit
integer. The address on the specified line device whose capabilities are to be
queried. An address identifier is permanently associated with an address; the
identifier remains constant across operating system upgrades. valid value of
dwAddressID is in the range 0 to dwNumAddresses – 1. The client obtains
dwNumAddresses from the LIVEDEVCAPS obtained by sending a GetDevCaps packet to
the remote server. This parameter is not validated by TAPI when this function
is called.</p><p><b>dwTSPIVersion (4 bytes): </b>An unsigned 32-bit
integer. The version number of the TSPI to be used. The high-order word
contains the major version number; the low-order word contains the minor
version number. This number is obtained by <a href="7c69dced-7bee-4ec8-a02e-f90b7afcfba6" data-linktype="relative-path">NegotiateAPIVersion</a>.</p><p><b>dwExtVersion (4 bytes): </b>An unsigned 32-bit
integer. The version number of the service provider–specific extensions to be
used. This number is zero if no device-specific extensions are to be used.
Otherwise, the high-order word contains the major version number; the low-order
word contains the minor version number. This value is obtained for this device
by sending the NegotiateExtVersion packet. This parameter is not validated by
TAPI when this function is called.</p><p><b>lpAddressCaps (4 bytes): </b>An unsigned 32-bit
integer. The size, in bytes, of a <a href="35ff7865-1349-41e3-923d-41557e795a69" data-linktype="relative-path">LINEADDRESSCAPS</a> packet
that is filled with address capabilities information upon successful completion
of the request. On successful completion, this field contains the offset, in
bytes, of the packet in the <b>VarData</b> field.</p><p><b>Reserved2 (4 bytes): </b>An unsigned 32-bit
integer. This field is used for padding and MUST be ignored on receipt. It can
be any value.</p><p><b>Reserved3 (4 bytes): </b>An unsigned 32-bit
integer. This field is used for padding and MUST be ignored on receipt. It can
be any value.</p><p><b>Reserved4 (4 bytes): </b>An unsigned 32-bit
integer. This field is used for padding and MUST be ignored on receipt. It can
be any value.</p><p><b>Reserved5 (4 bytes): </b>An unsigned 32-bit
integer. This field is used for padding and MUST be ignored on receipt. It can
be any value.</p><p><b>Reserved6 (4 bytes): </b>An unsigned 32-bit
integer. This field is used for padding and MUST be ignored on receipt. It can
be any value.</p><p><b>Reserved7 (4 bytes): </b>An unsigned 32-bit
integer. This field is used for padding and MUST be ignored on receipt. It can
be any value.</p><p><b>Reserved8 (4 bytes): </b>An unsigned 32-bit
integer. This field is used for padding and MUST be ignored on receipt. It can
be any value.</p><p><b>VarData (variable): </b>Present on successful
completion of the request. Contains a LINEADDRESSCAPS packet.</p><dl>
<dd>
<p>The contents of this field MUST be DWORD-aligned, as
specified in <a href="../ms-dtyp/cca27429-5689-4a16-b2b4-9325d93e4ba2" data-linktype="relative-path">[MS-DTYP]</a>
section <a href="../ms-dtyp/262627d8-3418-4627-9218-4ffe110850b2" data-linktype="relative-path">2.2.9</a>.</p>
</dd></dl></div>