Everything you need to know about importing a pet can be found on the BVet website:
http://www.bvet.admin.ch/themen/0161...x.html?lang=en
Yes, a cat needs to be chipped to bring him/her into Switzerland, and yes, the standard US chip is sometimes not readable here. Chips must conform to ISO 11784 or Annex A of ISO 11785, or if you already have a US chip implanted you must bring your own chip reader. (Scanners aren't all that expensive in the US.)
But do note - while bringing your own reader will get you through customs, a non-EU readable chip won't help you much if your cat gets lost during your sojourn here - so implanting an ISO 11784 or Annex A of ISO 11785 chip is really your best option.
Click on the pdf,'Traveling with pets - dogs, cats, fettets from third countries' for specific information.
Whenever you have questions it's best to go to the official source. Contact the BVet by phone or email - they have always been very helpful whenever I've had questions.
To contact the Federal Veterinary Office (FVO):
Tel +41 (0)31 323 30 33
Fax +41 (0)31 323 85 22
info@bvet.admin.ch
Hope you and your cats enjoy your time in Switzerland.