That's what your commlink is for, checking peripheral hardware for glitches. It'd be an Analyze roll.
If your datajack could run an Analyze program on it's own, then it could run any program on it's own. Were that the case, it would be a commlink. Were that the case, no one in the Sixth World would need a commlink at all.
A datajack is a piece of hardware interpreting brain signal into electronic signals. It has enough to do without software.

Maybe those old, ASIST datajacks from 3rd that otaku used...but that's a whole other can of worms.

The Analyze program needs input from something in order to analyze it. This input is provided by sensors within the device.
Also, the datajack has an internal data storage and chipreader.
Like all cyberwear, it is by default capable of wireless interfacing, so needs modem functionality for that.
All this beside having the modem functionality you described.
It's a full fledged device, hence has a device rating, and is a node. So can be clustered.

It is not, however, a commlink, as a commlink is especially designed to run an OS that allows it to run all of these nifty things we call Programs.

If that's the case, then the datajack has an OS provided by it's System Rating determined by it's Device Rating. If it has the capacity to run an Analyze program, why does it not have the capacity to run a Data Search program?

It doesn't have the capacity to run either an OS or any Program because it's a peripheral node. The same holds true for credsticks and your imagelinked sunglasses.

Peripheral nodes, indeed all nodes that want to do a thing in software, have to use a program to do it. They do have an OS, it's their System rating.
The difference is that peripheral devices can only run programs they were designed to run.

So, what programs is a datajack designed to run?

Probably only drivers.

I agree, commlink optimization does not affect socials tests that are boosted by empahy software for exactly the reasons stated.

I just want to put in again that the peripheral node limitations are *the* reason for clustering.

That's a good argument against allowing Optimization on Empathy. It's not really ironclad, but it's fair.

There is, however, a great deal of difference between these programs, and Programs.

A datajack runs software to at least allow it to perform the functions I have noted above. It needs to translate normal signals into ASIST signals, be able to run chips on its own, modem electronic signals into some kind of magnetism to allow it to communicate wirelessly, and translate whatever sensor output it has to a format that's understood by a standard Analyze program. Beyond that, it of course has a dedicated OS and firewall to run as well, plus presumably a UI to allow the user to use the OS to turn all of this functionality on and off.

Does anyone else find it weird that empathy software doesn't act like other sensor software? Most sensorsofts use their rating as a dicepool, but empathy software adds its rating to your dicepool. What's up with that?

Yeah. Like I said, changing that is one of the easiest fixes, and satisfyingly coherent.

It does both, actually. If you are using it in a Sensor, it can act just like any other sensor. If used directly in opposed tests, it adds its dice to the character's roll. In the latter instance, I personally prefer using it as a Teamwork Test, adding a number of dice to your test based upon the sensor's roll, to a maximum of the Character's Skill Rating, just like any other teamwork test. But RAW adds directly to the skill test. The one balancing factor in that is that the system requirements for higher rated Empathy Software requires a higher rated system to run it. We do not use the emotitoy as it is written. You want Empathy Software in a stand-alone package, you use either Camera's or Drones. *shrug* Whadda ya gonna do?