I am asking a question as a part of library maintenance for electrical equipment. We have installed a POS machine with credit card swipe on the same outlet as a laser scanner (used to check in books). Apparently, the POS gets a signal immediately that a swipe has occurred and failed before a swipe occurs. If the laser scanner is plugged into a different outlet (we are using an extension cord), everything works. Using extension cords in a commercial facility is prohibited, so does another outlet need to be added? What could be causing the POS to get a swipe signal? Thanks in advance for your help!

  • \$\begingroup\$ POS = Point of sale, not the other thing... \$\endgroup\$ – Funkyguy Aug 27 '15 at 16:44
  • \$\begingroup\$ correct, it is a Point of Sale unit that has a cash drawer and a screen to process payments. There is also a credit card swiper attached to the device. \$\endgroup\$ – Maribel Cabrera Ibrahim Aug 27 '15 at 16:48
  • \$\begingroup\$ A thought comes to mind, are the two pieces of machinery still next to each other regardless of which outlets? If you separated the two to put the laser scanner on a different outlet, then a lot of factors were also removed. \$\endgroup\$ – Funkyguy Aug 27 '15 at 16:49
  • \$\begingroup\$ Funkyguy, if the laser scanner is moved farther away, but still plugged in the same outlet, the swipe fails. If the laser scanner is close, but plugged into a different outlet, the swipe works and does not time out. \$\endgroup\$ – Maribel Cabrera Ibrahim Aug 27 '15 at 17:21
  • \$\begingroup\$ Alright, then I still stand by my answer \$\endgroup\$ – Funkyguy Aug 27 '15 at 17:21

Interesting, it sounds like your laser scanner is causing noise on the power cable which then interferes with the POS machines operation. This is probably due to a poorly designed power supply in either of the machines.

If you can't use just a different outlet, then it might be worth trying to put a ferrous nugget around the power cable of the POS machine before you spend the money to put in a new outlet.

A ferrous nugget serves to filter out noise on power cables and many products have them.

  • \$\begingroup\$ Thanks for this. I will see if we can do this... might be a quick fix. \$\endgroup\$ – Maribel Cabrera Ibrahim Aug 27 '15 at 17:23
  • \$\begingroup\$ @MaribelCabreraIbrahim You may also be able to use a plug-in noise filter, such as homedepot.com/p/… for example. I don't know what country you're in so you might have to find the correct product for your electrical system. \$\endgroup\$ – DoxyLover Aug 27 '15 at 18:54

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