Apple is defending its decision to market the latest iPad as a 4G-compatible device, answering a complaint from the Australian government’s consumer watchdog.

The company said Thursday in an Australian federal court that its decision to tout the tablet as 4G was not deceptive, the Australian reported. The tablet, which is compatible with 4G networks in the United States, does not work on Australian 4G networks. Apple has offered refunds to Australian consumers who felt they were misled by Apple’s marketing.

Apple has said that it was clear from before the launch of the iPad that its tablet would not work with the 4G networks in Australia.

Apple’s Australian Web site says that its iPad works on the country’s “HSPA, HSPA+ and DC-HSPA” networks, without mentioning the “Ultrafast 4G LTE” that it promotes on its Web pages in America and Canada — the only countries where the iPad is 4G LTE-compatible.

The dispute over the iPad touches on another point of contention on the labeling of the world’s mobile networks — namely what exactly is 4G. Apple is running into problems because the LTE frequencies of U.S. and Australian networks aren’t compatible.

The International Telecommunications Union, a standards-setting body for telecommunications services, identifies just two technologies as “true” 4G networks: LTE Advanced and WiMax Release 2, which aren’t as widely deployed.

But, technically, carriers can (and do) apply the 4G branding to LTE networks, WiMax networks and HSPA+ networks with the blessing of the ITU because they provide a “substantial level of improvement in performance...with respect to the initial third-generation systems now deployed.”

That’s why U.S. carriers all advertise 4G networks, though each is running a slightly different flavor: Verizon’s 4G network is an LTE network; AT&T’s is a mix of LTE and HSPA+; T-Mobile runs an HSPA+ network. Sprint is the odd man out on the WiMax standard but is building LTE infrastructure.

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