card reader problem: random card rejects

I have a card reader that will randomly reject cards (card misread) for no reason. I figured we should have the contractor replace the reader which they did, still getting random rejects. I looked through previous invoices from our contractor and this reader has been replaced several times.

Any ideas on the problem?

What is the distance from the reader to the access panel? The limit with Wiegand is 500 feet, and that's with the proper wire. What wire is used in the circuit? It's supposed to be shielded, NON twisted pair. What access system is it? Some systems will give errors if the card does not match the settings in the system. Is there any information in the event log? What is the reader mounted on or near? Some high voltage interference might affect the card reads. Is it the same card all the time? Does the same card work at the other readers? Does the same reader sometimes read a card and sometimes reject the same card?

Its CCURE, the panel is one level below, definately not more than 500ft.

nothing in the event log just card rejected, misread.

There is another card reader right next to this one and it works fine.

People get a card reject then use it again and it works fine.

Ok, for a temporary trial, can you switch the reader ports? Take the wires from port A and put them on port B? To see if the problem stays with the reader or with the port it's hooked to. I'm sorry I don't recall, did you try re-running the wire?

Also, does this particular system have the ability to operate without contact with the server? Could it be that the panel is losing comm with the server and denying because it can't access the database? That's probably a longshot, but you mention nothing in the log at all. That leads me to think there's a short in the wire somewhere.

If you are still having problems with this reader and hope its a HID.

Run your drain from card reader to battery neg at the panel.And or the purple wire witch is ground

reference to battery at the panel neg. this should clear up any randoms reads from data.

Four years later, I'd hope they would have sorted it out by now!