Wireless credit card machines are using GPRS signals for their work. GPRS wireless frequency band is a part of the cell phone frequency range and it can work in the range of GSM, 3G, CDMA and other mobile phone frequency ranges. So if you want to successfully block the work of wireless credit card machines you can use any of 3G/GSM jammers, whichever you will like more.
Still if you want to block the work of any wireless credit card machine without blocking the work of your cell phone there are few ways you can achieve this. First of all you can use advanced 4G smartphone because GSM and 3G signal blockers cannot jam 4G frequency. But if you have more ordinary cell phone then the only way you can jam wireless credit card machines without blocking your own mobile phone is to discover the working frequency of the particular wireless credit card machine you want to block and order multifrequency jammer with this frequency pre-programmed in it.
Although this type of signal jammer has its primary purpose of being used indoors as the stationary desktop jammer, you can use it from your bag in any way, it only cannot fit into your pocket. But it has enough power to deal with the wireless credit card machine effortlessly and not only with it.
answered Apr 17 '12 at 10:01