Motorola and T-Mobile responded Tuesday to requests from Sen. Al Franken (D-Minn) for more details on how they use Carrier IQ software.

In its letter to Franken, T-Mobile revealed that it uses the device on some of its premium smartphones including the HTC Amaze and the Samsung Galaxy S II. It estimates that 450,000 of its customers “use devices that contain Carrier IQ’s diagnostic software” to collect some information, such as the telephone numbers a user dials and the phone numbers from incoming calls. It does not collect the content of text messages sent or received, the content of e-mails sent or received, the URLs of Web sites visited, information from users’ address books or any other keystroke data.

Motorola replied that it installs software on four models — the Admiral, Titanium, Bravo and Atrix 2 — at the request of its carrier partners, AT&T and Sprint.

“As of the end of the third-quarter of 2011, we have sold a total of approximately 145,000 units of these models to our wireless carrier partners,” wrote company government relations senior vice president Dale Stone. However, Stone said, Motorola has no mechanisms in place to track how many of the devices are currently in use or how the devices are collecting data.

Carrier IQ, which makes software of the same name designed to measure network diagnostics, found itself at the center of a firestorm over privacy after a security researcher posted a video showing the program making note of every key press he made on his device.

The company has since said that the video showed a version of its software that was incorrectly installed on HTC devices, and reaffirmed that its program is not designed to log keystrokes, keep the content of text messages or look at the content of Web sites. But the clarification came only after scrutiny from lawmakers. U.S. government officials have confirmed that the Federal Trade Commission is looking into Carrier IQ’s practices; Sprint has plans to remove the software from all of its devices.

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