Abstract: An integrated circuit (1a) for a transponder (1), wherein said integrated circuit (1a) is switchable between a TTF (transponder talks first) and an RTF (reader talks first)-mode within a switching timeframe (TF2), wherein the position of the switching timeframe (TF2) is shif table in relation to a timeframe (TF1) allocated to the TTF-mode. In a preferred embodiment, the switching timeframe (TF2) is before a timeframe (TF1) allocated to the TTF-mode by default. After initialization of the transponder (1), the switching timeframe (TF2) is switched to a position after the timeframe.

Abstract: A circuit has a first memory for modifiable storage of information, the information being modifiable by an ambient parameter of the circuit, which ambient parameter acts on the first memory. The first memory includes a test memory area for storing test information. The circuit also includes a second memory for unmodifiable storage of reference information and a detection circuit. The test information and reference information is supplied to the detection circuit. The detection circuit then detects whether a modification of the originally stored test information has been brought about by an ambient parameter acting on the first memory.

Abstract: An integrated circuit (1a) for a transponder (1), wherein said integrated circuit (1a) is switchable between a TTF (transponder talks first) and an RTF (reader talks first)-mode within a switching timeframe (TF2), wherein the position of the switching timeframe (TF2) is shif table in relation to a timeframe (TF1) allocated to the TTF-mode. In a preferred embodiment, the switching timeframe (TF2) is before a timeframe (TF1) allocated to the TTF-mode by default. After initialization of the transponder (1), the switching timeframe (TF2) is switched to a position after the timeframe.

Abstract: In a circuit (2) comprising a first memory means (5) for modifiable storage of information (I), the information (I) being modifiable by an ambient parameter of the circuit (2), which ambient parameter acts on the first memory means (5), there is firstly provided in the first memory means (5) a test memory area (7) for storing test information (TI) and there is secondly provided a second memory means (16) for unmodifiable storage of reference information (RI) and there is thirdly provided a detection means (19), to which detection means (19) there may be supplied the test information (TI) which may be read out from the first memory means and the reference information (RI) which may be read out from the second memory means (16) and which detection means (19) is designed, with the aid of the read-out test information (TI) and the read-out reference information (RI), to detect a modification of the originally stored test information (TI) brought about by an ambient parameter acting on the first memory means (5).