In general, there is no special protocol or behavior for how state and federal employees interact in the United States.
My background: I worked for about 5 years in my state's legislature as a program analyst. I often contacted federal agencies and Congressional staff for various reasons. Currently I work in my state in science policy, where I frequently interact with funding agencies such as the NSF, NIH, etc.
Generally, I just call up the federal agency and talk to them in the same way that I would call my local city offices.
The most difficult part of talking to someone in the federal government is finding them. In my experience, 99% of the people out there won't want to talk to you. Not out of malice, they just aren't in public facing jobs and don't want to deal with the public. They will probably refer you to their agency's public information office or someone similar. These people seldom have great information, but may be able to point you in the right direction. Working through them is typically slow.
With some research you may be able to find contact information for the person who you really want to talk to. Contact them directly. Explain who you are and what you want. I usually use something like this:
The State Division of Forest Lore is interested in applying to next year's pathfinding training colloquium. Based on your agency's website, I believe you are the program official to contact with applications. Could you let me know when next year's colloquium will be held? Will it still be in Nevada?
Apologies if this was sent to the wrong person in error. If this is the case, can you please direct me to the correct person or department?
A few important features of this script:
- Explain who you are and what your relationship is to the agency right away. If you haven't been in contact with this person before, they will need contact to know how to respond to you.
- Clearly state your request.
- Give them an out in case they are the wrong person to contact. In most cases you will get referred to someone else.
Sales for federal agencies are often planned when their budget is set. They likely won't be able to commit to a new purchase until the next budget year at a minimum. Don't be surprised if you have to play a very long game.