Q: I read your November column (see tinyurl.com/za3ftm4) about a Minnesota man who was having a huge data usage problem with his Verizon MiFi device (which converts a cellular signal into a Wi-Fi hot spot for PCs and other gadgets.) You suggested that a hacker might have accessed his MiFi. I'm having the same problem, but, unlike him, I don't leave my device turned on when I'm not using it. And I'm careful to observe that there's only one user accessing the MiFi when I use it. Given that, can a hacker be the cause of my problem?
Mary Gray, Wilmington, N.C.
A: I've changed my mind about the cause of this problem. The real cause is that Verizon Wireless doesn't sufficiently warn customers to expect dramatically higher data usage if they connect a MiFi Internet access device to a computer.
That has caused many MiFi users to overrun their Verizon Wireless data plans, and as a result pay higher monthly service fees. And there have been many complaints about it, including some from people who said they turned off their MiFi devices when they weren't being used.
Richard Larson, a MiFi user in Chippewa Falls, Wis., said that, "For no apparent reason, my data usage increased nearly four times my previous average, which nearly tripled my bill."
Ken Lapre, a MiFi user from Fredericksburg, Va., said his relatively large 20-gigabyte monthly MiFi data plan is exhausted before the month is over. As a result, "I usually shut down my PC and rely on my iPad for a week or so."
There are similar complaints about MiFi data use in online forums, such as the Verizon Wireless "community" website (tinyurl.com/ncmkk4w), where the MiFi is called by the brand name Jetpack, and a non-company site (tinyurl.com/zohpl9j.)
When I asked Verizon Wireless about all this, the company responded with an e-mail that didn't acknowledge that complaints about MiFi had been made. It focused on how consumers can manage data use, particularly on PCs.
Meagan Dorsch, a Verizon Wireless spokeswoman in Colorado, said that customers should turn off their MiFi devices when they're not in use, not just log off, which leaves the device running. And they should be aware that PCs can use the MiFi whenever it's on.
"Often customers aren't even aware that computer programs or applications are running in the background that require Internet access," Dorsch said. "Our newest mobile hot spots [MiFi devices] allow customers to proactively manage their usage, with displays showing data usage in real time and identifying how many devices are connected."
Technically, PCs may be to blame. But in a larger sense, Verizon Wireless is to blame for selling a product whose usage costs weren't clear.
I suggest that consumers avoid using their PCs with the data-limited Verizon Wireless MiFi device, and instead use them with unlimited data plans from cable TV or land line telephone companies.
Contact Steve Alexander at Tech Q&A, 425 Portland Ave. S., Minneapolis, MN 55488-0002; email firstname.lastname@example.org.