Will an Army Reserve 25U who is deployed with a finance unit get sent into the field with combat units?

It's very well possible, needs of the Army can place you well outside your comfort zone.

You could get pulled to support a combat unit, and despite your MOS whatever it is, it is to provide support to the warfighter. Additionally, whatever your MOS, you are expected to be able to operate a weapon system. Everything is in the realm of the possible while deployed, I know Paralegals and Cooks who have seen combat.

Don't ever confuse yourself with an Infantryman, their job is to practice combat. You are however, a Soldier, and all Soldiers are expected to support the fight and to be riflemen if the time comes.

RTO's are valuable, and despite the 25 Useless and RC jokes you'll hear so is your skill set.

Yeah anyone could go no matter your MOS, that's why we have rifle quals and things of that nature. I'm not saying you'll be kicking down doors but IEDs and Indirect are pretty equal opportunity.

I can say that, as a 25U myself I was deployed in 09 to kohst provenance Afghanistan and there was a need for my mos with some of the combat multipliers in the AO so I was tasked out from my original unit which was an aviation unit to do some dismounted missions as an RTO. So it is possible

Your trained in basic for infantry first. If you are needed for combat in the field, you will be sent more than likely.

Finance units are employed as distributed teams. I'd expect that you would be sent to different locations to support them unless they are getting area support from other signalers. You'd get there by ground or air. What exactly are you asking?

Added:
- If ÿou are part of a ground movement, everyone is in a combat patrol. Doesn't matter MOS. Every soldier is a soldier first and your MOS second when it hits the fan.
- if you are assigned to one unit, you could be attached or placed under operational, tactical, or administrative control of another unit that needs the MOS. Example: if your unit is overstrength and the other unit is understrength by USR or an emergent mission requirement. This is the exception and not the rule. How your unit uses some personnel is Up to the Commander and their determination of mission requirements.
- you may be leveraged as a 25B. My experience is they go where they are needed but most of the time, with HHC.
- they don't randomly stick people in Rifle Companies, much less someOne from another unit that is not combat arms or authorized in a combat arms unit.
- guard duty is MOS immaterial.

You'll normally deploy with the unit you're in. Unless there's a need, people don't get cross-leveled much anymore.

You are a soldier. Why do you think they have weapons quals, CTT and such? You will do what you are ordered to do and go where you are ordered to go. If you can't handle that, then why are you in?

Expect to be used as a 25B and you will spend much of your time as tech support. You need to get aligned to the Signal Command in either Georgia, 335th or Hawaii, 311th. When you are in your AIT make sure you get all the different positions your peers and school are aware of.

As a 25 series you are headed to a FMSU, which with transition it reverting back to FI BN. You will be responsible for supporting the finance equipment and ensuring the systems needed to get soldiers all pay and entitlements are up and running.

We send finance teams forward to support soldiers in their forward locations, but in my experience 25series stay back with larger, more permanent Theater support systems.

You would be deployed with the finance unit. But, if you switch units or volunteer to deploy you could end up going overseas with a combat unit. Anything can happen, so even as a support MOS be aware that you may be in combat or a combat unit if need be.