This attribute counts the total number of times that the T401 timer
has timed out within a data call. If this timer times-out frequently,
the operator may need to adjust the provisional parameter T401
acknowledgment timer to a larger time amount, since every time
that V.42 sends out a frame it sets the T401 timer to wait for the
peer's acknowledgment of the frame. When the timer times-out and
no acknowledgment has been received, the V.42 sends the same
frame to its peer. The counter wraps when it exceeds the maximum
value.