I dont think its anything to do with the frequency as I bought a second hand Astro 220 and DC30 collars from a Fella on a hunting page on facebook from over there and they work perfectly here in Southern Ireland. I did see some of the astro 320 for sale on ebay say they wouldnt work here but another fella said his would as it hadnt the latest software installed. I would say if you knew a good computer programmer he could probably uninstall the software no bother. Let us know how you get on.