The Technical Assistance Service (SAT) is the department or company in charge of the maintenance or repair of the products to which it is linked.

When a product is purchased, the manufacturer or marketer of the product is obliged to respond for possible manufacturing defects during a certain period (warranty), which varies according to the legislation of each country/continent. It is in these cases that the Technical Service intervenes, which may be owned by the manufacturer/marketer or in most cases an external subcontracted company.

Once the product is no longer covered by the warranty period, the user is free to contract maintenance with any other technical service. This is why there are a large number of unofficial technical services, that is, they are not linked to any specific manufacturer or marketer, but act at their own risk.

Although the term SAT is used by service workshops that repair equipment with a manufacturer's warranty, there is another more specific acronym for this type of workshop: CAST “Authorized Technical Service Center”, these centers are differentiated by handling a volume of repairs much higher than the SAT and by having to carry out careful control of the guarantees.

CAST's must comply with various rules imposed by the manufacturers to whom they provide their services, the objective is to offer an excellent service for their clients and in this way preserve the image of the brand they represent.

Sometimes, when talking about SAT, some companies refer to the computer tool that companies or technical service departments use to manage their entire volume of work. These helpdesk programs record and manage notices and repairs, work orders or maintenance, preventive or corrective contracts.

CASTs, unlike SATs, are very often forced to obtain quality certificates, both in the industrial field and in customer satisfaction. Quality certificates can be obtained by acquiring specialized management systems that require compliance with guarantee management processes but at the same time optimize the relationship with customers.