C12 VCC Time-out Period. A LE Client SHOULD release
any Data Direct VCC that it has not used to
transmit or receive any data frames for the
length of the VCC Time-out Period. This parameter
is only meaningful for SVC Data Direct VCCs.
This time value is expressed in seconds. The default
value is 20 minutes. A value of 0 seconds means that
the timeout period is infinite. Negative values will
be rejected by the agent.