Session Close
(corresponding to T
SMPClose
in the C.S0024 standard) specifies the time period for which the test set has not heard from the AT before sending a
SessionClose
message to the AT.
The test set and AT use the keep-alive mechanism to verify that peer is still alive. Once a session is open (see
Session Open State
), the session close timeout timer is started. If the test set has not heard from the AT for at least 1/3 of
Session Close
timeout period, it sends a
KeepAliveRequest
message to the AT. When the test set receives a
KeepAliveResponse
message from the AT, the test set resets the session close timeout timer and repeats the above process. If the test set does not receive a
KeepAliveResponse
message (or other messages from the AT) for at least 1/3 of
Session Close
timeout period, it sends a
KeepAliveRequest
message to the AT again. If the test set does not receive any response by the time the session close timeout timer expires, the test set assumes that the session with the AT has been lost. The test set will send a
SessionClose
message and go to
Idle State
. Also, an error message is posted to indicate that the session times out.
Setting the
Session Close
to zero turns off the session close timeout timer. In this case, the test set does not try to send
KeepAliveRequest
messages, and will not automatically close the session if not detecting any traffic from the AT.
The session close timeout timer is disabled while a data connection is present. When a traffic channel connection is present, the Call Drop Timer is used but note it can be disabled.
Session Close
timeout is a "Configurable Attribute" that is configured during the
Session Negotiate State
. Its value can not be changed when a session is open and
Call Limit Mode
is on. If session close timeout is changed when a connection is open, the connection will be closed. You will have to re-open the connection.
During hybrid mode tests, to prevent the session from unexpected closing when the AT stays on the IS-95/IS-2000 system (for example, a voice call) longer than the default value (3 minutes), it is recommended set the
Session Close
to a larger value. See
How Do I Make Hybrid Mode AT/MS Tests?
for details. (Note that the
Session Close
on the front panel defaults to minutes while seconds are used by the GPIB command by default.)