MP3 (MPEG Audio Layer III) is a standard format for audio compression technology. By using MP3 a file can be compressed to one-tenth the size of the original.
WMA (Windows Media^TM Audio) is format for audio compression technology. WMA files can be compressed to a size smaller than MP3 files.
This main unit has limitations on the MP3/WMA file standards and recorded media and formats that can be used.

• Supported standards: MPEG-1 Audio Layer III

• Supported sampling frequencies: 44.1, 48 (kHz)

• Supported bit rate:
64, 80, 96, 112, 128, 160, 192, 224, 256, 288, 320 (kbps)
* Supports VBR (64~320kbps).
* Does not support free format.

• Supported channel modes: monaural, stereo, joint, dual

• Supported standards:
WMA Ver. 7
WMA Ver. 8
WMA Ver. 9

• Supported sampling frequencies: 32, 44.1, 48 (kHz)

• Supported bit rate:
48, 64, 80, 96, 128, 160, 192, 256, 320 (kbps)

* Supports VBR (48~192 kbps).

* Does not support lossless compression.

* Does not support WMA files recorded at a frequency of 48kHz with a bit rate of 96kbps.

MP3/WMA files have an "ID3/WMA Tag" that allows input of information so that data such as song title and artist can be saved. This main unit supports ID3v. 1.0, 1.1 and WMA tags.

The media capable of playing MP3/WMA include CD-R and CD-RW discs. Compared to the CD-ROM media commonly used for music discs, CD-R and CD-RW discs are fragile in high temperature/high humidity environments and one section of the CD-R and CD-RW may become incapable of playback. Fingerprints or scratches on the disc may prevent playback or cause skipping during playback. Sections of a CD-R or CD-RW may deteriorate if left inside a vehicle for long periods of time. It is also advisable that CD-R and CD-RW discs be kept in a light-blocking case because the discs are vulnerable to ultra-violet light.

The format of discs to be used must be ISO9660 Level 1 or Level 2.
The control items for this standard are as follows:

• Maximum directory layers: 8 layers

• Maximum characters for folder names/file names: 32 (including "." and 3 letter file extension)

• Allowable characters for folder names/file names: A~Z, 0~9, _ (underscore)

• Maximum number of files on a single disc: 256

• Maximum folders this main unit can recognize: 192*

*: A root directory is counted as one folder.

Only files with the MP3/WMA file extension ".mp3" / ".wma" can be recognized as MP3/WMA and played. Be sure to save MP3 files with the ".mp3" file extension. Be sure to save WMA files with the ".wma" file extension. The "MP" letters of the file extension will be recognized whether entered in upper case or lower case.

Multi-sessions are supported, and CD-R and CD-RW discs with annotated MP3/WMA files can be played. However, when "Track at once" has been written, close the session or process the warning message. Use the same format for each session (don't change the format).

When a disc with recorded MP3/WMA files is inserted, the main unit first checks all the files on the disc. No sound is output while the main unit is checking the files on the disc. It is recommended that the disc be recorded without files other than MP3/WMA files and without unnecessary folders in order to speed up the checking of disc files by the main unit.

It is possible that the playing time will not be correct, depending on the writing condition of the MP3/WMA file.

* It is possible that the playing time will not be correct when VBR Fast Up/Down is used.

The names of MP3/WMA folders and files within the same level are displayed in the following order.

1. MP3/WMA folders are displayed first, in ascending order of numbers, letters.

2. Files are displayed next, in ascending order of numbers, letters.