Patent ID: 6976111

Claim:
A removable expansion module for a portable host, referred to as the first-level module, for engagement with a portable host when inserted into an opening in the host, the first-level module comprising: an expansion module frame and a PCB; a host-interconnect for coupling with the host when the first-level module is inserted in the opening in the host; an I/O interconnect for coupling with an external I/O device; I/O adapter circuitry for the I/O device; a second-level interconnect for coupling with a second-level expansion module; and second-level adapter circuitry coupled to the second-level interconnect; wherein the first-level module has an opening sized and positioned to allow insertion of the second-level expansion module into the opening so as to engage the second-level interconnect while the first-level module is engaged with the portable host, and to allow withdrawal of the second-level expansion module from the opening so as to disengage from the second-level interconnect while the first-level module is engaged with the portable host.