Over at AllShadow.com, tipster ND4SPD has unearthed what appears to be a help file that details the operation of feature called Alternate Line Support (ALS) from the ROM of the upcoming Touch Pro2 on T-Mobile. Here’s exactly what the help file says:

Overview of Alternate Line Support

Alternate Line Support (ALS) allows you to switch between two phone lines for making and receiving calls on your device. The Line 1 is selected by default for which you can configure phone settings, such as ring type, ring tone, and more by tapping > Settings > Personal tab > Phone > Phone tab on your device. However, you can configure a ring tone while selecting either of the phone lines.

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Choose alternate phone line

1. Tap > Settings > Personal tab > Phone > ALS tab.

2. Select the desired phone line, such as Line 1 or Line 2.

3. Tap the Ring tone for list and select a ring tone for the selected phone line.

4. Tap Play icon to play back and listen to the ring tone.

5. Tap OK.

Notes

• If this service is not available on your device, please contact your wireless service provider for more information.

• To change phone settings or access ALS from the Phone screen on your device, tap Menu > Options. For more information about phone settings or how to change ring type and ring tones for your current phone line, see the related help topics.

Does this mean that the T-Mobile Touch Pro2 would have dual-SIM support (like the Acer DX900)? Possibly. The Touch Pro2 will be marketed as a business device, and it’s possible that a lot of businesspeople deal with two phones lines, thus having ALS may be a huge draw for these professionals. Also, we’re thinking that this feature may be a way for T-Mobile to differentiate a device that will be on most major carriers across the world in due time.