How to open CALLTO files

Did your computer fail to open a CALLTO file? We explain what CALLTO files are and recommend software that we know can open or convert your CALLTO files.

What is a CALLTO file?

The CALLTO file extension indicates to your device which app can open the file. However, different programs may use the CALLTO file type for different types of data.

While we do not yet describe the CALLTO file format and its common uses, we do know which programs are known to open these files, as we receive dozens of suggestions from users like yourself every day about specific file types and which programs they use to open them.

We are continually working on adding more file type descriptions to the site, so if you have information about CALLTO files that you think will help others, please use the Update Info link below to submit it to us - we'd love to hear from you!

Generic CALLTO

These apps are known to open certain types of CALLTO files. Since many different programs may use CALLTO files for different purposes, you may need to try a few of the apps to open your specific CALLTO file.

RingomaxRingomaxUser submitted
PTT JAPANPTT JAPANUser submitted
PTTJapanPlusPTTJapanPlusUser submitted
UcallWeconnUcallWeconnUser submitted
GlobalTalkGlobalTalkUser submitted

Try a universal file viewer

Try a universal file viewer like Free File Viewer. It can open over 200 different types of files - and most likely yours too. Download Free File Viewer here.

We have not verified any programs that we know for certain can work with CALLTO-files on Mac. If you know one, please use the Suggest link below and tell us about it!
We have not verified any online services that we know for certain can work with CALLTO-files. If you know one, please use the Suggest link below and tell us about it!