A diesel exhaust after-treatment system for a vehicle includes a precious metal primary diesel oxidation catalyst and a precious metal secondary diesel oxidation catalyst. A data code indicative of a collective state of one or more subsets of the emergency devices is communicated during cyclic communication from the slave to the master whereas information indicative of the individual states of the emergency devices is communicated during acyclic communication from the slave to the master. The system also includes a digital imager receiving image data and converting the image data to digitally encoded image data. The blocking can be carried out at the user’s computer, at the gateway to which the user’s computer is connected, etc. The plurality of sidewalls include a first mating sidewall that is connected to a first intermediate sidewall, the first intermediate sidewall being connected to a second intermediate sidewall, and the second intermediate sidewall being connected to a second mating sidewall.