%
% stack: ack-brand now-brand expected step
%
 !Act.Next
 *trakactz
 {
%
% got proper response
%
  pop +Act.Next *trakactx
 }
 {
%
% no response yet, see if received invalid response
%
  _Act.Received
  {
%
% got improper response, try step again
%
   pop2 "response" -Act.Next *trakactx
  }
  {
%
% just haven't received anything yet, check timeout
%
   "Act." &_Act.Tracker _
   any?
   {
    Time.Now
    "s" Time.Diff
    120 gt
   }
   {
    true
   } ifelse
   {
%
% waited 2 minutes, should have response, try step again
%
    pop2
    "overlong" -Act.Next *trakactx
   }
   {
%
% not past timeout
%
    pop2nd _Act.Next *trakactx
   } ifelse
  } ifelse
 } ifelse