NEW YORK (TheStreet) -- Sprint's (S) new Spark data network ceases to work when a device on the network makes a phone call, according to a Consumerreports.org published story Thursday.
Sprint stock was trading at a high of $9.55 but took a sharp downturn, and is now down 0.3% to $9.35.
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"While we can't yet say for sure if such speedy connections are easy to find, or even possible, Consumer Reports engineers have confirmed that Spark can't do what older Sprint 4G used to be able to do: make or maintain cellular data connections during phone calls," the article says.
"That means no Web browsing, e-mail checking, Facebook or Twitter postings, or Map or GPS navigation assistance while you're on a call, unless you can access a Wi-Fi hot spot," the article continued.
This would be a step back for the new Spark network which had promised to provide some of the fastest data speeds -- 50-60 megabits per second -- of any network in the country.