This depends on if you have an A0 or A1 truck.
I elaborate below but the quick answer is, for A1 the non military software is better than the IETMs for troubleshooting the electronic subsystems of the truck. For an A0 you do need the military software for the ICE interconnect box to be able to take readings from the truck and report them to your PC.
If you have the DPA III Plus adapter that normally comes with the ICE kit, you can download the drivers online from DGtech. You will want the “legacy” drivers which, last time I was on their site, had a picture of the military version of the adapter. Once you load the drivers there are a few basic applications included for free that will pull the codes from all of your subsystems. When I first connected mine it pulled codes from CTIS, ABS, engine and transmission. If you want to dive into the weeds of these systems you will need the vendor specific software. For example for CTIS you would want the Dana Diagnostic Tool. This will let you reprogram pressure settings and troubleshoot/test the system. Anyone trying to work on CTIS without this is going to struggle. For the engine you would need CAT ET. This costs money normally but if you are crafty online you can find “cracked” versions. Someone can correct me if I am wrong but for the ABS you would use Wabco software, and the transmission is Allison Doc I think. All of this is only using the DPA III Plus.
the rest of the ICE kit is mainly used for taking readings and feeding that data back into the military IETM software so that it can analyze the results and walk you through the troubleshooting steps. Most of what that unit does can be replicated with other manual means like a Voltmeter and pressure gauges. On an A1 FMTV you do most of the interfacing with the J1913 port and the DPA. The older A0 trucks and other military vehicles like the humvee have the DCA port which is used to tap into a lot of the sensors of those older platforms. The ICE interconnection Box let’s you interface with that connector and take readings on your computer if you have the right ICE software.
folk doing searches to find threads on topic they want to educate themselves on prior to asking clarification questions, or starting new threads.