<div class="content"><p>The DevSpecific 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 MUST be used as a general extension mechanism to enable a
TAPI implementation to provide features that are not described in the other
TAPI functions. The meanings of these extensions are device specific.</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">dwRequestID</p>
  </td>
 </tr>
 <tr>
  <td colspan="32">
  <p align="center">lpContext</p>
  </td>
 </tr>
 <tr>
  <td colspan="32">
  <p align="center">hPhone</p>
  </td>
 </tr>
 <tr>
  <td colspan="32">
  <p align="center">lpParamsContext</p>
  </td>
 </tr>
 <tr>
  <td colspan="32">
  <p align="center">lpParams</p>
  </td>
 </tr>
 <tr>
  <td colspan="32">
  <p align="center">dwSize</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>The identifier of the
function that will be invoked on the remote server. This value MUST be set to
92.</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 nonzero
request ID value indicates that the request is in progress and will complete
asynchronously, and a <a href="b1c6fae0-09ca-4f7b-85f6-1324376d231c" data-linktype="relative-path">PHONEERR_Constants</a>
value indicates synchronous failure.</p>
</dd>
<dd>
<p>Returns a positive request identifier if the
function will be completed asynchronously or a negative error number if an
error occurs. The <i>dwParam2</i> parameter of the corresponding <a href="8f5bc349-fd55-46f2-b0bc-dc9f757317a9" data-linktype="relative-path">LINE_REPLY</a> packet is 0 if
the function succeeds, or is a negative error number if an error occurs. If the
client specified a nonzero value in the <b>dwRequestID</b> field of the packet,
the same value MUST be used for the returned positive request identifier. The following
table lists common return values.</p>
</dd>
<dd>
<table><thead>
  <tr>
   <th>
   <p>Name</p>
   </th>
   <th>
   <p>Value</p>
   </th>
  </tr>
 </thead><tbody><tr>
  <td>
  <p>PHONEERR_INVALPHONEHANDLE</p>
  </td>
  <td>
  <p>0x00000013</p>
  </td>
 </tr><tr>
  <td>
  <p>PHONEERR_NOMEM</p>
  </td>
  <td>
  <p>0x0000001A</p>
  </td>
 </tr><tr>
  <td>
  <p>PHONEERR_INVALPOINTER</p>
  </td>
  <td>
  <p>0x00000015</p>
  </td>
 </tr><tr>
  <td>
  <p>PHONEERR_RESOURCEUNAVAIL</p>
  </td>
  <td>
  <p>0x0000001F</p>
  </td>
 </tr><tr>
  <td>
  <p>PHONEERR_OPERATIONUNAVAIL</p>
  </td>
  <td>
  <p>0x0000001D</p>
  </td>
 </tr><tr>
  <td>
  <p>PHONEERR_UNINITIALIZED</p>
  </td>
  <td>
  <p>0x00000022</p>
  </td>
 </tr><tr>
  <td>
  <p>PHONEERR_OPERATIONFAILED</p>
  </td>
  <td>
  <p>0x0000001C</p>
  </td>
 </tr></tbody></table>
</dd></dl><p>Additional return values are device specific.</p><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>dwRequestID (4 bytes): </b>An unsigned 32-bit integer.
The identifier of the asynchronous request.</p><dl>
<dd>
<table><thead>
  <tr>
   <th>
   <p>Value</p>
   </th>
   <th>
   <p>Meaning</p>
   </th>
  </tr>
 </thead><tbody><tr>
  <td>
  <p>0x00000000</p>
  </td>
  <td>
  <p>The server MUST generate a unique positive request ID
  to return as the Ack_ReturnValue.</p>
  </td>
 </tr><tr>
  <td>
  <p>0x00000001 — 0x7FFFFFFF</p>
  </td>
  <td>
  <p>The server MUST use this value instead of generating a
  unique positive request ID.</p>
  </td>
 </tr></tbody></table>
</dd></dl><p><b>lpContext (4 bytes): </b>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. </p><p><b>hPhone (4 bytes): </b>An <a href="0c93f481-3429-48c5-a9e6-f0568c4cabd9" data-linktype="relative-path">HPHONE</a>. The handle to a
phone device. This field MUST have been obtained by sending the <a href="6b5ee45e-b5c8-4148-a9b2-b16b9b995c3f" data-linktype="relative-path">Open</a> packet.</p><p><b>lpParamsContext (4 bytes): </b>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. </p><p><b>lpParams (4 bytes): </b>An unsigned 32-bit
integer. The offset, in bytes, in the VarData field of a parameter block. </p><p><b>dwSize (4 bytes): </b>An unsigned 32-bit integer.
The size, in bytes, of the parameter block that is indicated in the lpParams
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>MUST contain a parameter
block indicated in the lpParams field.</p><dl>
<dd>
<p>The contents of this field are DWORD-aligned.</p>
</dd></dl></div>