preferred design variant of the holder according to the invention with a fastening mechanism is also described in detail on the basis of two drawings in these fig3 shows a plan view of a holder with a retaining bracket in the basic position and fig4 shows a plan view of the holder according to fig1 with a smartphone seated in the receptacle the holder 50 shown in fig3 has a receptacle 51 for a smartphone the receptacle 51 comprises a fixed part 52 and a retaining bracket 53 which is movably mounted on the holder 50 the retaining bracket 53 engages with the longitudinal arms 52 a 52 b of the fixed part 52 and is displaceably mounted there the engagement prevents the fastening mechanism from being freely accessible and tampered with on a transverse side of the receptacle 51 formed from the fixed part 52 an electronic interface 54 based on a current standard is arranged to which a smartphone can be connected the holder 50 has an insertion opening 55 in which a token 56 is held a slider 58 is movably mounted in a groove 57 of the fixed part 52 the slider 58 in fig3 is located in its second position in which the fastening mechanism is unlocked the mechanism is therefore not blocked and the u shaped retaining bracket 53 can be withdrawn from the arms 52 a 52 b in order to allow a smartphone to be inserted into the receptacle 51 in the basic position of.