Acknowledgement
An IPA server must always respond with an acknowledgement message within TACK
seconds, if the message contains an ID. When the client requests an acknowledgement, the ID is added to the message as an attribute.
<TextMessage Id="100" To="123456">Text to display</TextMessage>
The server responds with an Ack message, copying the Id attribute. The Result attribute contains a result code, and the tag contents may contain the result as plain text. The result codes are inspired by HTTP codes, where 200 means "OK" and 404 means "Not found". A detailed list of IPA result codes can be found in an appendix.
If the message is delivered, the server will respond:
<Ack Id="100" Result="200">OK</Ack>
If the designated paging device is not found, the server would respond as follows:
<Ack Id="100" Result="404">Not found</Ack>