In a printer, page thickness is compensated for by measuring a displacement between a printhead and a print media support surface. A second classification signal may be transmitted to the calling-side gateway that adjusts the answer tone in response to the second signal. The hash key and the signature representation can be provided to a first device without exposing the contents of the signature to the second device, and the obfuscated signature can be provided to a second device without exposing the contents of the signature to the second device.