Not having MFG / model #, I can only hazard a few guesses... Phone and cable connections are often targets of lightening. Data port, I suspect, is to send data to the software you'd load on your PC for logs, control of the UPS, etc.
That function isn't really part of a UPS, its just an extra feature tacked on for a bit of "added value" or whatever the marketing lot call it. It sort of makes sense to integrate all your protection functions into one unit...
The UPS would have shipped with a cable which has an RJ45 connector on one end and a standard USB connector on the other. Load the included software on the PC, plug the cable into the UPS "Data Port" and the other end into the PC. You can now adjust various UPS parameters using a software interface and, perhaps more importantly, the UPS can notify the operating system of power outages and request the OS initiate an orderly shutdown before the UPS runs out of standby power.
The Cable In/Cable Out ports and Network-Phone In/Out ports provide surge suppression on those lines. If your outside cable-tv or telephone cable took a lightning hit, for example, the UPS would attempt to absorb the spike.