To start, certification is an extensive process that is applied to both the main chassis and to the individual telephones. The chassis of a certified system undergoes a thorough fifteen (15) step testing and inspection process before it is released for resale. This includes visual inspection for heat or voltage problems as well as voltage tests. In addition, each trunk/line circuit and each station circuit are individually tested to confirm operating performance. The mounting of each circuit board and power supply is checked and confirmed secure. Also systems with signs of extensive wear or use are eliminated from the "certified" selection process.
In addition to the chassis, each individual telephone goes through a ten-point test and evaluation. Among other testing procedures, individual buttons are all tested and confirmed to be working properly. The handsets are checked for quality audio transmission both incoming and outgoing. The cords are all tested and approved as well. Each set is cleaned and sanitized before being released for resale as well.
In addition, and just as importantly, National Telesystems performs a burn-in process for 48 hours on each system before certifying them for resale. Many problems that will not appear in a "cold" cabinet will surface during an extended "burn-in" period, and National Telesystems catches these before they ever leave the testing facility. The vast majority of pre-owned systems sold by other distributors never go through this kind of testing, and the customer becomes the guinea pig and has to handle the problems as they arise. That is not only a very frustrating experience but it is a very expensive one as well, in both time and money.
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