Filenames suitable for mobile phones

My mobile phone is not reading the file names of the tracks loaded on to my SD card. I have converted all of my files so that the tag reads ID3v2.3 (ID3v1 ID3v2.3). When I drag the files onto my SD card it only reads some of them and doesn't see the rest. I think it may have to do with the limit of 32 characters the phone software imposes on the file names, but I'm not sure. The files that are visible seem to be the ones with shorter names.

Has anyone else experienced this problem and if so, was the file name size the cause? If so, how do I reduce the file name to 32 characters or less?