A tachograph comprising: wireless communication means adapted to receive data from identification units of a first type, and a memory operatively connected to the wireless communication means, wherein the memory is adapted to store data received by the wireless communication means from the identification unit of the first type, wherein the tachograph further comprises communication means adapted to receive data from identification units of the first type, wherein communication means is also adapted to receive data from identification units of a second type, wherein the identification units of the first type and the second type are user identification cards of first and second type respectively, wherein the communication means comprises card reading means adapted to physically interface with identification cards of the first type and with identification cards of a second type, and thereby to exchange data with identification cards of the first type and second type, wherein the memory is operatively connected to the card reading means and adapted to store data received by the card reading means from identification cards of the first type and second type, wherein the card reading means has a card receiving slot being adjustable between having a first card slot dimension associated with identification units of the first type and a second card slot dimension associated with identification units of the second type, wherein the dimension of the card receiving slot is adjustable in a direction transverse to a longitudinal direction of an opening of the card receiving slot, wherein the second card slot dimension is greater than the dimension of first card slot dimension, wherein the second card slot dimension allows a thicker identification unit of the first type to be received by the card receiving slot, wherein the card receiving slot will have its first card receiving dimension in an idle state, wherein the tachograph further comprising processing means operatively connected to the memory and adapted to control the operation of the tachograph, and mechanical means that allows adjusting the card receiving slot, wherein the processing means is configured to determine whether the identification unit introduced into the card receiving slot is of the first or second type (17, 19) based on the resulting first or second card slot dimension of the card receiving slot. wireless communication means adapted to receive data from identification units of a first type, and a memory operatively connected to the wireless communication means, wherein the memory is adapted to store data received by the wireless communication means from the identification unit of the first type, wherein the tachograph further comprises communication means adapted to receive data from identification units of the first type, wherein communication means is also adapted to receive data from identification units of a second type, wherein the identification units of the first type and the second type are user identification cards of first and second type respectively, wherein the communication means comprises card reading means adapted to physically interface with identification cards of the first type and with identification cards of a second type, and thereby to exchange data with identification cards of the first type and second type, wherein the memory is operatively connected to the card reading means and adapted to store data received by the card reading means from identification cards of the first type and second type, wherein the card reading means has a card receiving slot being adjustable between having a first card slot dimension associated with identification units of the first type and a second card slot dimension associated with identification units of the second type, wherein the dimension of the card receiving slot is adjustable in a direction transverse to a longitudinal direction of an opening of the card receiving slot, wherein the second card slot dimension is greater than the dimension of first card slot dimension, wherein the second card slot dimension allows a thicker identification unit of the first type to be received by the card receiving slot, wherein the card receiving slot will have its first card receiving dimension in an idle state, wherein the tachograph further comprising processing means operatively connected to the memory and adapted to control the operation of the tachograph, and mechanical means that allows adjusting the card receiving slot, wherein the processing means is configured to determine whether the identification unit introduced into the card receiving slot is of the first or second type (17, 19) based on the resulting first or second card slot dimension of the card receiving slot.