Call for fire (CFF), the coordination of indirect artillery and mortar fires by a ground observer, is an ideal mission set for virtual environment (VE) training. CFF is a United States Marine Corps (USMC) core competency and is a perishable skill that requires frequent reinforcement training. The requirement to expose Marines to initial and recurrent CFF training is hampered by the expensive and time-consuming nature of live indirect fire training. The USMC currently has a CFF simulation training capability, but access is limited by the fixed site nature of the simulations. This paper presents the results of a proof-of-concept study that developed and tested a tablet-based CFF training simulation. The objective of this study was to investigate the comparative value of tablet-based CFF VE training. The research team designed and developed a tablet-based CFF prototype and then executed a user feedback experiment that compared the tablet solution to the USMC's current personal computer (PC) based CFF simulation, ObserverSim. The comparison focused on end user opinions regarding the training value and effectiveness of the tablet's multifunction interface relative to ObserverSim's traditional mouse and keyboard interface. End users with and without previous CFF experience registered an overwhelming preference for the CFF tablet prototype (p=0.002). While the tablet prototype was primitive and of much lower fidelity than ObserverSim, participants liked the tablet's ability to mimic real world physical motion, its ease of use, and shallow learning curve. These study results offer the modeling and simulation community important lessons learned and a realistic example of how to exploit the tablet's multifunction user interface to further training simulation development efforts.