I will go out on a wild limb and say Windows servers and either SQL Server or Oracle database.
Hate to break it to you, but that sounds more than adequate. I would choose differently if given the choice, but it's not a valid excuse for pausing 3 minutes to generate a job number by quite a long shot.
I actually agree, I wasn't making a good/bad comment, just speculating. Very few government contractors would bid a linux or open-source-software-based system.
I do agree, a well designed and implemented system running on Oracle and Windows can certainly handle something like 911 dispatch and do it well.