A modular signature and data capture device employs a standardized ISA 
bus, standardized communication ports, and standardized ×86 
CPU architecture to promote flexibility in using past, present, and future 
software and accessories. A VGA-
caliber backlit LCD is superimposingly combined with a pressure touch pad that is useable with a passive 
stylus. The LCD displays pen drawn signatures and 
graphics in real-time, and can display images and data stored in the device, or downloaded from a host 
system, including advertisements. The LCD can also display menus, device instructions, virtual pressure-sensitive data keys, and control keys. The device includes a built-in a three-stripe magnetic 
card reader unit. The device accepts PCMCIA-compatible accessories including 
solid state memory units and smartcards, and is compatible with plug-in accessories including an external PIN keypad entry unit, a 
fingerprint unit, an omnibus unit including a printer and check processor in addition to a 
fingerprint unit. Security is provided by DES-encrypting PIN data and / or using Master / Session and / or DUKPT 
key management, or by using 
fingerprint token data as a PIN. The invention may be used to conduct paperless transactions in which the merchant is paid in realtime. Further, merchant purchase profiles may be generated on a per-user basis to promote more effective advertising.