USB Communication Settings: What Is MSC Mode?

When to use MSC mode

An iPhone is connected by USB to a Mac laptop

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USB MSC (or more commonly referred to as just MSC) is short for Mass Storage Class.

It is a communication method (protocol) used for transferring files. MSC is specifically designed for the transmission of data over a USB interface. Typically this is used between a USB device (like an MP3 player) and a computer.

While browsing your portable device's settings, you might have already seen this option. If your MP3 player/portable device supports it, you'll normally find it in the USB settings menu. Not all devices that you plug into your computer's USB ports will support MSC. You may find that some other protocol is used instead, like MTP for instance.

Even though the MSC standard is older and less capable than the more intuitive MTP protocol, there are still a lot of consumer electronic devices on the market that support it.

This USB transfer mode is also sometimes called UMS (short for USB Mass Storage) which can be confusing. But, it is exactly the same thing. 

What Types of Hardware Can Support MSC Mode?

Examples of the types of consumer electronic devices that typically support MSC are:

Other consumer electronic devices that can support MSC mode include:

  • Digital cameras.
  • Digital Video Recorders.
  • Other multimedia devices.

When you plug a USB device into your computer that is in MSC mode, it will be listed as a simple storage device that will most likely appear with just a drive letter assigned to it. This contrasts with MTP mode where the hardware device takes control of the connection and will display a user-friendly name such as Sansa Clip+, 8Gb iPod Touch, etc.

Disadvantages of MSC Mode for Digital Music

As previously mentioned, a device that is in MSC transfer mode will be seen as just a normal storage device, like a flash drive. If you want to sync digital music then this isn't the best USB mode to use.

Instead, the newer MTP protocol is the preferred mode for synchronizing audio, video, and other types of media files. This is because MTP can do a lot more than just basic file transfers. For instance, it facilitates the transfer of related information such as album art, song ratings, playlists, and other types of metadata which MSC can't do.

Another disadvantage of MSC is that it doesn't support DRM copy protection. In order to play DRM copy-protected songs that you have downloaded from an online music subscription service, you will need to use MTP mode on your portable media player rather than MSC.

This is because music licensing metadata will be required to be synced to your portable in order to play the subscription songs, audiobooks, etc. Without it, the files will be unplayable.

Advantages of Using MSC

There are times when you will want to use a device in MSC mode rather than the more full-featured MTP protocol. If you have accidentally deleted some of your song files, for example, you'll need to use a file recovery program to undelete your MP3s. However, a device that is in MTP mode will have control of the connection rather than your computer's operating system. It won't be seen like a normal storage device and so your recovery program probably won't work.

MSC has an advantage in this scenario because its file system will be accessible just like a normal removable drive.

Another advantage of using MSC mode is that it is more universally supported by different operating systems such as Mac and Linux. In order to use the more advanced MTP protocol on a non-Windows computer might need third-party software to be installed. Using MSC mode negates the need for this.

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