Typically end-device testing is the least time consuming and expensive level of testing if the designer is using a certified module. If they are not using a certified module, then the costs can skyrocket. In one white paper, AT&T listed a $175,000 upcharge for end device certification if they were not using a certified module. All of these estimates assume passing certification on the first try. The expense of changing a design and retesting can be much higher. One testing house stated that many customers underestimate the expense of certification by an order of magnitude. Mistakes like this can kill a project. Even so, if a user’s unit volumes justify the cost and time to market delay, using a module can be the best way to go. That is a decision a designer will need to make with their team. There is another option available if uncertainties still remain about the unit volumes that will sell, or if getting to market quickly is important.