Track Numbering - Is There An Industry Standard for Maximum Number of Digits

Is there an industry standard for the maximum number of digits used in the track number field?

I have recently found myself using MP3 Tag to add metadata to files for a daily TV show/podcast that I listen to. The content creator did not fill in the "Track" field, but I like to use that field to get the files to sort chronologically. I have been using the episode date for a track number, eg, 2014 March 5 becomes 140305. Yesterday I discovered that my portable mp3 player only reads the last three digits of that number, but Windows Media Player reads all six digits and sorts the file correctly.

I have been wanting to contact the ministry that produces this content and talk to them about proper mp3 tagging for the benefit of those of us who download the files and play them on various devices. Given my recent experience, I'm wondering what track numbering convention to recommend. Is three digits considered the industry standard or is my mp3 player a little odd, or perhaps old?

I realize this isn't a MP3 Tag specific inquiry, but perhaps the answer will help others, especially those who may be using the software to tag files for a daily podcast.

I don't believe it's a part of any specification. ID3v1 had no track number field. ID3v1.1 took two bytes from the end of the comment field to allow for one byte to hold a track number. The first byte has to be a zero (NULL) byte. That means that the maximum track number in an ID3v1.1 tag is 255.

Since TV shows typically have episode and/or season numbers, there's no need to use the air date for track numbering. There are any number of ways to easily work around devices that have a limitation to the maximum track number. For instance, you might use disk number or album name to group each season.