This attribute shows the reason for the most recent state change.
notStarted - this is the default state after SVC data link has just been
created.
abmeEntered - SVC data link has entered Asynchronous Balanced
Mode after SABME or UA has been received.
abmeReset - the data link has been reset.
dmReceived - DM response received.
dmSent - DM sent.
discReceived - DISC response received.
discSent - DISC sent.
frmrReceived - FRMR received.
n200RetranTimeOut - retransmitLimit has been exceeded.
other - unspecified state change reasons. The most likely reason for
this is the transition from state waitingAck to state
informationTransfer.