I got a strange problem. We are in Hawaii. We have been using FreePBX for about 8 years now. Quite recently (maybe the last 6 months) we have noticed that some of our calls (in or out) and some of our clients calls, they only get one way sound… sometimes.
One of our clients processes around 3,000 calls a month. Most of them work fine. But the person that uses the phone the most has noticed (she asks) that if the people they are calling out to, or calling in - are using a TMobile account, that is when they can not hear properly - 1 way sound.
She ends up having to call them on her personal cell phone.
Today, I am working with a new client setting up Zoiper on their cell phones. (I also use Zoiper on my cell phone) After jerking around for like 45 minutes, I cant get their sound to work. All are android phones. On my phone with the same version of Zoiper and same settings, my phone works fine. It turns out, both of their phones are TMobile also.
I honestly hate to think it is a TMobile problem, But I have checked the firewall settings and compared the settings of 5 different systems we manage - and everything looks fine. but only “some” calls can not pass sound, and it is starting to look like tehy are all TMobile phones.