$work{"$f[2]$stream"} = $ref; # store in work
$busy{$f[2]} = $ref; # set interlock
$self->send(DXProt::pc30($f[2], $f[1], $stream)); # send ack
$work{"$f[2]$stream"} = $ref; # store in work
$busy{$f[2]} = $ref; # set interlock
$self->send(DXProt::pc30($f[2], $f[1], $stream)); # send ack