The new iPad on Verizon Wireless' 4G LTE network can also run on AT&T's data network when an AT&T SIM card is inserted in the Verizon device, early buyers have found.
Spokespersons for AT&T and Verizon separately said they had no comment on the discovery when queried by Computerworld.
In both cases, a micro-SIM card from an iPhone 4S running on AT&T's network was inserted into a new iPad from Verizon Wireless, taking the place of the existing SIM card. The iPad's carrier setting also had to be updated to support connections to AT&T in both cases.
Also, in both cases, the AT&T SIM card worked over AT&T's 3G network, but not its faster LTE. The Verizon iPad supports the same GSM frequency bands for non-LTE bands (including EDGE and HSPA+) as for iPads sold for AT&T, hence the interoperability.
Part of the beauty of GSM networks is that they rely on using SIM cards that carry a user's account, phone number and identity from device to device, so the discovery may not be all that surprising. MacRumors theorized that Apple could have restricted the AT&T SIM card's operation over other networks, but did not.
Because Verizon's 3G network is not GSM-based, it doesn't rely on using SIM cards, which means there would be no Verizon SIM card (from another device like an iPhone) to insert into an AT&T iPad.
That factor would seem to give the advantage to Verizon in selling the new iPad, since Verizon's customers could take advantage of both Verizon's and AT&T's 3G data networks, while AT&T iPad customers would have no similar advantage.
On the other hand, Verizon users would still need to buy a SIM card from AT&T, and since the AT&T SIM card reduces the capability of the Verizon iPad from 4G to 3G, it raises questions about the value of the discovery, industry officials noted. A SIM card from AT&T won't work inside a Wi-Fi-only version of the new iPad.
Matt Hamblen covers mobile and wireless, smartphones and other handhelds, and wireless networking for Computerworld. Follow Matt on Twitter at @matthamblen or subscribe to Matt's RSS feed . His email address is email@example.com .
Read more about mobile and wireless in Computerworld's Mobile and Wireless Topic Center.