The one for the Smart Modem would have been in the device.. unless you removed it for some reason, it should still work.. easy way to test is to disconnect the NBN dservice by pulling out the cable in the red WAN port or the grey DSL port of the modem. If you have the correct SIM inserted, then the modem will switch to 4G backup mode - Blue light on the front. If you have the wrong SIM in there it might not switch to 4G backup. In that case, swap the SIM's.
Stevo 52
Too many devices, probably an addict :-) also a tinkerer and developer of stuff..
Not with Telstra, just another customer like you!
Hello