<div class="content"><p>The GetDevCaps 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 a specified phone 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">hPhoneApp</p>
  </td>
 </tr>
 <tr>
  <td colspan="32">
  <p align="center">dwDeviceID</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">lpPhoneCaps</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">Reserved9</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>The identifier of the
function that will be invoked on the remote server. This value MUST be set to
95.</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
MUST contain the result of the encapsulated telephony request. A value of 0
indicates success, and a <a href="b1c6fae0-09ca-4f7b-85f6-1324376d231c" data-linktype="relative-path">PHONEERR_Constants</a>
value indicates failure. The remote server MUST complete this call
synchronously.</p>
</dd>
<dd>
<p>Returns zero if the request succeeds or a negative
error number if an error occurs. Common return values are:</p>
</dd>
<dd>
<table><thead>
  <tr>
   <th>
   <p>Name</p>
   </th>
   <th>
   <p>Value</p>
   </th>
  </tr>
 </thead><tbody><tr>
  <td>
  <p>PHONEERR_INVALAPPHANDLE</p>
  </td>
  <td>
  <p>0x00000008</p>
  </td>
 </tr><tr>
  <td>
  <p>PHONEERR_INVALPOINTER</p>
  </td>
  <td>
  <p>0x00000015</p>
  </td>
 </tr><tr>
  <td>
  <p>PHONEERR_BADDEVICEID</p>
  </td>
  <td>
  <p>0x00000002</p>
  </td>
 </tr><tr>
  <td>
  <p>PHONEERR_OPERATIONFAILED</p>
  </td>
  <td>
  <p>0x0000001C</p>
  </td>
 </tr><tr>
  <td>
  <p>PHONEERR_INCOMPATIBLEAPIVERSION</p>
  </td>
  <td>
  <p>0x00000003</p>
  </td>
 </tr><tr>
  <td>
  <p>PHONEERR_OPERATIONUNAVAIL</p>
  </td>
  <td>
  <p>0x0000001D</p>
  </td>
 </tr><tr>
  <td>
  <p>PHONEERR_INCOMPATIBLEEXTVERSION</p>
  </td>
  <td>
  <p>0x00000004</p>
  </td>
 </tr><tr>
  <td>
  <p>PHONEERR_NOMEM</p>
  </td>
  <td>
  <p>0x0000001A</p>
  </td>
 </tr><tr>
  <td>
  <p>PHONEERR_STRUCTURETOOSMALL</p>
  </td>
  <td>
  <p>0x00000021</p>
  </td>
 </tr><tr>
  <td>
  <p>PHONEERR_RESOURCEUNAVAIL</p>
  </td>
  <td>
  <p>0x0000001F</p>
  </td>
 </tr><tr>
  <td>
  <p>PHONEERR_NODRIVER</p>
  </td>
  <td>
  <p>0x00000019</p>
  </td>
 </tr><tr>
  <td>
  <p>PHONEERR_UNINITIALIZED</p>
  </td>
  <td>
  <p>0x00000022</p>
  </td>
 </tr><tr>
  <td>
  <p>PHONEERR_NODEVICE</p>
  </td>
  <td>
  <p>0x00000018</p>
  </td>
 </tr></tbody></table>
</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>hPhoneApp (4 bytes): </b>An <a href="55b72ff6-9236-401b-846a-e8a78dfada1b" data-linktype="relative-path">HPHONEAPP</a>. The handle to
the application registration with TAPI. This field MUST have been obtained by
sending the <a href="a600d262-0bb1-447b-8a0d-6f57d3a8ec18" data-linktype="relative-path">Initialize</a>
packet.</p><p><b>dwDeviceID (4 bytes): </b>An unsigned 32-bit
integer. The identifier of the phone device 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>dwTSPIVersion (4 bytes): </b>An unsigned 32-bit
integer. The version number of the TAPI 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 using <a href="59e34869-7701-4eb5-95d4-f8ce908ce17a" 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 obtained by using <a href="6ee86f03-d1e2-4823-98e1-9e5fc97c11bc" data-linktype="relative-path">NegotiateExtVersion</a>. It
can be zero if no device-specific extensions are used. Otherwise, the
high-order word contains the major version number; the low-order word contains
the minor version number.</p><p><b>lpPhoneCaps (4 bytes): </b>An unsigned 32-bit integer.
The size, in bytes, of a <a href="92710f40-6a08-4121-953c-5c3eb19aa59e" data-linktype="relative-path">PHONECAPS</a>
packet that contains phone device capability information on successful
completion of the request. </p><dl>
<dd>
<p>On successful completion, this field contains the
offset of the packet in the VarData field.</p>
</dd></dl><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>Reserved9 (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>MUST be present on
successful completion of the request. MUST contain a PHONECAPS packet.</p><dl>
<dd>
<p>The contents of this field are DWORD-aligned.</p>
</dd></dl></div>