When I insert my credit or debit card at a gas-station pump, the machine then tells me to remove my card “quickly”. Why “quickly”? Will the machine mess up my card if I leave it in too long?
Thanks for any help.
For security reasons. You’re supposed to whip it in and out and back in your wallet quickly, in case a robber sees it and tries to rob it from you. Then the gas station is liable, that’s why they ask you to remove it quickly.
That makes sense. Thanks for replying.
I don’t think that is why. I think it is to keep the card from being stuck in the machine.
No, you remove your card quickly because that’s the way the machine reads it. If you stick your card in and leave it there, the equipment won’t read the magnetic strip on the card correctly.
Showing your credit card is a lot safer than whipping out a big wad of bills.
That is not right. The card is read while it is in the machine, not as you take it out.
This is pure speculation, but I think it’s just because they don’t want you to forget the card in the slot. These card readers (typically) don’t “suck” in your card like and ATM and then spit it out when done. The card is only sticking in part way. An overzealous gas pumper, or someone in a hurry might just immediately start pumping and forget the card.
But then again, there is that loud, annoying BEEPING when the reciept is printed, so nevermind…
The most rewarding part was when I got my money!
-Dr. Nick Riviera
I agree, because if they didn’t want you to forget the card, they would ask you to remove it slowly, you’d remember it more that way.
I think the real reason they want you to remove it quickly is so that you’ll hurry up and let the next person in line go.
Bob’s right. A magnetic stripe is read by moving it past a “read head” which detects the tiny electric currents induced in the head as the magnetic fields encoded on the card move by. No movement, no current, no read. And the faster you move it the more current is generated, i.e, the better the signal and the less likelihood for an error.
Think of those cash machines (and card readers at the grocery store) where you don’t insert the card at all – you just swipe it through the slot. Try sticking your card straight into the slot without swiping it. Nothing happens. (Other than curious looks from the cashier.)
My guess is that they decode the stripe while you’re pulling the card out, rather than when you insert it, because you are more likely to remove the card in one smooth motion than you are to insert it smoothly.
There is probably a minimum speed required for a successful read. Experiment with it if you like – remove the card verrrry slowly and see if it still works. Or try pulling it out in a series of jerks rather than a single pull.
“To do her justice, I can’t see that she could have found anything nastier to say if she’d thought it out with both hands for a fortnight.”
Dorothy L. Sayers
Busman’s Honeymoon
Here’s a word of advice at gas stations: When paying (at the pump) PRIOR to pumping, the machine has no clue how gas you intend to buy. To approve your purchase, the credit card cos. view such purchases in blocks of about $30 per visit - covering just about everyone’s fill-up needs. Once the actual amount of your charge comes in, the $30 pseudo-charge is adjusted.
Boy, was I surprised to learn this the hard way when I was supposedly “over my limit” because of these $30 stupid blocks. I had a gas-guzzler, and I my credit limit was modest. I never let the balance climb high, anyway. So, you can imagine my shock! The bank was slow in adjusting these $30 blocks, and they add up fast with a gas-guzzler!
In my tenure as a student, I worked at a number of restaurants, stores, etc. where customers used credit cards. If you swipe the cards slowly, for some reason it makes it harder for the machine to read it. Even old, beaten-up cards could sometimes be made to work by swiping them super-fast.
Sucks to your assmar.
Also, you will notice that you have to swipe in a certain direction (i.e. down and not up) So I would guess that the reader is only unidirectional. Trying to insert the card fast, is likely to bend the card and not get any good read. Pulling it out fast is much easier and so the reader reads one way and requires a bit of speed to read.
It is for the purposes of reading the card that you should pull it out fast.
Jeffery
In a past life as a light petroluem distilate distrobution technician, it was $50 that the machine authorizes on your card. Also, you can only use a CRIND (Card Reader In Dispenser) machine 3 times in a 24 hour period. That used to get the people filling all of their cars up in one day all sorts of upset.
Jeremy…
Nobody ever calls me after they’ve done something smart.
I’m going to exceed my knowledge here but the principle is that the reader doesn’t detect the magnetic fields on the card directly – it senses the change in the magnetic field as the head moves from one magnetic region to another (or, more precisely, as the regions move past the head). The more abrupt the change, the stronger the signal. Moving the card quickly makes the change more abrupt.
That’s why old reel-to-reel tape recorders used such big reels – you had to get the tape moving past the head pretty swiftly to get a good signal. Nowadays the technology, both in the recording medium itself and in the detection circuitry, have improved to the point where you can get oodles of data on a cassette or a floppy disk.
Another way to increase the signal strength is to get the head closer to the medium. The read/write head on a hard disk drive actually flies over the disk, kept aloft by the air currents created by the whirling disk. But this allows it to maintain a very small clearance so the magnetic regions can be very small and still produce a good signal. Smaller regions equals more data. (There are other factors involved, too, notably maintaing precise positioning of the R/W head.)
That’ll do, pig. That’ll do.
Thanks to everyone who’s responded so far. So the general consensus seems to be that the machine needs speed to read. I’ll play around with it the next time I fill up.