My IU was working fine. Immediately after exiting a carpark, and presumably having successfully paid the carpark charges, the IU started starting beeping and displaying this “Err” code. Ok, maybe the cash card contacts were dirty. I cleaned the cash card contacts and tried again, but still received the “Err” code. I’ve a spare cash card. I tried the spare one, and it also had an “Err” code. I thought perhaps the problem was with the IU itself.
It was night, and I couldn’t see the symbol clearly. Even in the day, the symbol wasn’t so easy to make out. Had the symbol been more conspicuous, I could have focused more attention on the cash card itself. However, I had just used one cash card successfully, a few seconds before the “Err” display appeared. My second cash card had the same error. What is the likelihood that two different cash cards have an error at the same time?
What was the real cause of the problem?
After wasting time and effort, and also anger that the IU wasn’t warrantied for the life of the car, I found that the problem was that my cash card had expired. Both my cash cards had expired, on the same day. Such a coincidence. I hadn’t bought both cash cards at the same time, but I suppose by some unfortunate chance, they were both of the same batch and thus expired at the same time.
Why, oh why, couldn’t the fellows at LTA, or the fellows who designed the IU, use their common sense to think of a more helpful display message? I know, the 7-segment LCD has some limitations. But perhaps “EHP”, where the letter “H” could be accepted as an approximation of the letter “X”, would work? If anyone couldn’t figure out what EHP meant, they could Google search for an answer. Or go to LTA’s website to find out. Something. Anything. Just not “Err”.
What is even more strange about this episode is that the cash card expired the previous day! Yes. On the night after the cash card had expired, it was still working. There was no “Err” display. I was still using it to pay my carpark charges. Then suddenly after the last successful payment, the “Err” display appeared.
People, if you’re going to be designing software, systems, or products of some kind or other, think about how they are going to be used, and how to make it easy for people to use. If you really need help working 7-segment LCDs, a Google search is just a click away.