Don't know if they're all the same, but the Digitax agent sticks the gizmo into the meter - which I think is merely required to gain access to the calibration variables - but he then inputs the data manually.
Each tariff has has numerous different variables, and what he does is change the relevant variable with the new variables, and they are supplied by Digitax head office.
For example, variable 1 might be the flagfall yardage, variable 2 might be the flagfall price, variable 3 might be the subsequent increment in yards, variable 4 might be charge for the subsequent increments, variable 5 might be the waiting time increment in seconds etc.
For example
1 might be keyed in as 800 (yards)
2 might be keyed in as 220 (pence)
3 might be keyed in as 240 (yards)
4 might be keyed in as 20 (pence)
Then obviously the meter uses all this data to calculate the fare.
The meter has the potential to use dozens of variables, but since the Fife tariff is fairly straightforward only a handful of them are used.
Obviously if the agent just gets one digit wrong, then the meter could read ridiculous amounts - for example, if the third variable as entered as 24 rather than 240 and if the fourth variable was entered as 200 rather than 20 then the meter would be clocking up £2.00 every 24 yards rather than 20p every 240 yards
