By: Lic. Adrin J. Rosemary The SAT does not know what to invent! She is one of the many phrases (or pretexts) that I have listened throughout the last year when I am in front of a client who must migrate to the scheme of electronic invoicing; and I make emphasis in the word because there are people who must by fiscal obligation and the rest that would have by the sum of operative advantages and economic that to make the change represents, everything is question to be informed, advised well and to lose the fear. One is not money because there are very accessible options, is not information because there is very many throughout and certainly one is not technology because it is obligation of all business of being updated beyond its specialty. After to have seeded (and until multiplied) the terror in the Mexican contributors, of to have set out the great delay in the matter of technology and to lie down to average country raises, finally we are seeing with clarity the horizon or as " is said colloquially; the light at the end of tnel". The problems were many in practice at the time of making the change but between most common has been: " what option is better for my business in 2010 average own or to contract an authorized supplier? " , " I remained with the arms cruzados in 2010 and now I need to certify my invoices and nonencounter to no CAP in my ciudad" , " that fulanito he said this to me but in the course they said another thing, my accountant thinks different and the SAT not me resolvi" , good, he could fill to leaves and leaves of these problems but no as serious as one: We initiate 2011, with this obligation to certify the invoices (CFDi) and there was no company that certificara! , clearly, there will be one who leaves to say that another CAP published by the SAT was one, but were 4 and only 1 at the time " half prestaba" the service to which it could.