How to change ringtones

any one tell me how to change ringtones of freepbx and Grandstream voip phones.

Many Grandstream phones allow you to upload an audio file as a ringtone.
I think you can upload 3. There is a secton in the GS manual about this.

I’m not sure if they respond to the bellcore dr allerts.

Google " upload Grandstream Ringtones" and you’ll get this:

It’s ALWAYS a good idea to search the internet for your problem. Probably 95% can be answered that way. You’ll save time and usually resolve your problem more quickly than posting and waiting for a reply.

Don’t get me wrong…this forum is excellent. I’ve found many an answer here. But, many of the questions have been answered in this forum or another venue.