I went through the manual and could not find info on how to reset the reader. However this info could allow anyone to compromise you credit card device.

I used to work for serveral computer companies and we always had codes for the systems that were not public but if you needed you could call support to get it. So in this case you will most likely contact VeriFone and/or your credit card service provider to get the code if they setup the device.

VeriFone, Inc.
2099 Gateway Place, Suite 600