5g internet and Ooma telephone

  • 25 March 2022
  • 3 replies


Anyone having any trouble with the Ooma telo going offline and back online constantly throughout the day? Mine will show the blue ready/online symbol on the device but if i check the dashboard status for the telo device it will sometimes come back “offline” quite a few times a day. When it is in this mode you can’t call out or receive calls. You get a dialtone but calls don’t go out, get a fast busy after a little delay. Ooma is telling me after multiple calls and troubleshooting that it is the internet and amount of “jitter”. I’ve done speed tests and sometimes jitter is very low and the next time high. Ooma says it should be <5. Mine sometimes in the 20’s and 30’s, and at times it’s under 5.


3 replies


I just got a 5g t-moble router and hooked up my old omma phone first gen telo i can call out just fine. But if I call in you can here the them but they cant here you!!

tried re boot  i get a dail tone still an issue

The funny thing is my OOMA goes offline a lot and after speaking to T-Mobile IT they explained that voip and Cellular Internet it's not a good mix, but i found out later T-mobile offers OOMA themselves.  not sure if the issue is with OOMA, or T-mobile.    


I tried these as well - it helped some, but not fully:


Ooma Telo device needs the following ports and protocols to be open in your router to ensure trouble-free communication:

Remote: (Outgoing Firewall Rules)
    UDP/TCP 53
    UDP/TCP 1194
    UDP/TCP 1294
    UDP 67
    UDP 123
    UDP 3480
    UDP 10,000 to 20,000

Local: (Incoming Firewall Rules)
    UDP 49,000 to 20,000

Make sure that the above required ports are open. In addition, we also recommend that the router feature called UPnP is ENABLED and SIP ALG is DISABLED.




I’ve had Ooma for about 8-10 years and it has worked great for me.  I’ve had T-Mobile Home Internet for about a year.   Ooma worked great with T Mobile home internet up until about 2 months ago (around Oct ‘22) and then all of a sudden the calls (both sides of the call) started having much distortion and lost words.  At times it was almost unusable.  I called both Ooma and T-Mobil looking for a solution but neither could help me.  Ooma had me check the jitter and it ranged from under 10 at times to over 300 at other times, sometimes one test right after another with great variability.   fyi.  My T Mobile Home Internet speeds are good ranging from about 60mbps up to over 300 at times….so I don’t think speed is the problem.   I’ve thrown in the towel on Ooma in combination with T-Mobile Home internet.  My only guess at this point is that T-Mobile changed the cell towers near me or the traffic increased about 2 momths ago making Ooma unusable.  Has anyone else experienced this?  I’ll be switching to a cheap cell phone plan with Tello ($10/mo) hooked up to a home phone system with link2cell functionality.  At least with that I can actually hear what people are saying to me.