Modular, portable data collection terminals are disclosed for use in mixed wireless and hard-wired RF communication networks, wherein various radio transmitter modules and associated antennas may be selectively added to a base terminal unit to solve networking problems associated with specific types of business environments. Structured representations of a current state of an event-driven application are accessed, one with respect to a plurality of client-tier environments. Data packets transmitted on the network and having corresponding classification rules are classified according to generated classification rules. In an embodiment, the image orientation parameter may be modified from a default configuration. One exemplary release mechanism utilizes a resiliently held element that is moveable by hand against the resilience, and another employs a hand slideable latch.