To ask a necessary question, does it have a sim card? If not connection will be via wi-fi/bluetooth and will be o.k. if that device is o.k. Actually even with a sim you should be able to connect through other devices provided you have loaded the software in both devices.(Call and Text)
the SM-T580 is Wi-Fi only, it doesn't have a sim, doesn't connect to mobile networks, so has nothing to do with the 3G shutdown.
The 3G shutdown scare is in relation to devices that are sold as "phones" and aren't capable of VoLTE(Voice over LTE) due to either the owner not updating them, the manufacturer not providing ongoing support(could be carrier hasn't tested them for it) or they are purchased overseas, so not compatible with Telstra, which runs a non standard VoLTE, requiring specific requirements in the firmware.
Slight update. Some tablets have sim cards and can make phone calls, so those models might need checking. Saw a reference to this in an isp advice message.
