VoIP with t-home internet

I had the 4G LTE gateway for several years. It worked fine with both Grandstream HT702 and Obi200 ATA VOIP adapters. I upgraded to the NOKIA 5G21 ("trashcan") and neither worked. Some people say they have used IP and other back-end equipment with it while others say they cannot. After hours with T-Mobile Home Internet techs, they suggested I try the Arkadyan KVD21 5G gateway. It works fine with my equipment. The GUI is very limited, so I cannot say whether users needing more advanced options would be able satisfy their needs. The 4G LTE gateway GUI had many advanced network specifications available, way beyond my skill level. 

[Note: The first KVD21 I had lost its Internet connection every few hours. I exchanged it quickly and without hassle at my local T-Mobile store. The replacement has been up for two days and seems stable and fine. Download speeds to my Cat6 cabled computer run between 70 Mbsp and well over a hundred. Upload speeds are not so stellar but adequate for my needs.]

I had the same problem, which started the moment I switched to the TM 5G service. This happened with BOTH of the MJ devices I had in service. By chance, I found that this MJ issue was solved when I connected an old wired router--with port speed limit of 10Mbps. I have a newer wired router now, which lets me "downspeed" by port. I have them set for 10Mbps, full-duplex. I don't know why the MJs fail with ports  running faster. Or maybe it's something peculiar with TMs 5G, which is worked around by down-speeding.

I'm having a new problem now with the 2 MJs; frequeent distorted voice and little echo bits and such. This happens even if the network is stripped down, with nothing else running (e.g. no PCs, TVs, anything). I even bought an Ooma VoIP device and have similar problems with that. From what I can see, you can't do qos configurations on the 5G router. But Ooma allows for "pass through" configuration, meaning you can put it between the ISP router and the rest of your network. Ooma says that will result in the best voice quality (which makes sense), but it's still not very good. Still working on this issue...

Person wrote:

Person wrote:

Just spoke with a girl called Crystal from the customer service . Waiting time was zero minutes. She told me that they are aware of the "problem" that many VOIP devices can't function by default. She also assured me that it's a matter of sending request to register a particular device with them (in my case it's a Grandstream GS-GXP2140 VOIP desk phone). Which she did sent.

She collected my download and upload speed (asked me to test it in real time).

I am still kind of skeptical based on reviews here that say that all these reps do is lying to you. However, she told me to wait 24-72 hours and gave me "complaintID" I could use to  track the status of the request.

I’ll keep you guys posted.

Ok, here is my report: nothing happened. Nobody contacted me, the problem wasn't fixed. At all.

Classic TMobile Customer Service: Very polite and courteous, but they do not help you resolve the problem! I hate calling their customer service because it takes an enormous amount of time, they offer contradictory information, and have no accountability for the wrong information they give you.

I quit their service, for the same reason.
I use VOIPLY.  I *like* VOIPLY.  I use them through Comcast.  I would much rather use them through T-Mobile internet (there is a T-Mobile tower two blocks from my house, and I use T-Mobile for mobile phone service).
After trying T-Mobile internet, which I was totally satisfied with except for VOIP being blocked (and also, HORRIBLE, incompetent, obnoxious staff at 6864 Reisterstown Road, 21215), I quit and switched back to Comcast.  I would much rather use T-Mobile, but as soon as they stop blocking VOIP!

I have used Ooma home VoIP for several years. During Covid with cable internet (very fast speed) I can major issues. The problem was jitter and the cable node being bombarded by Zoom from Home school kids. Everyone focuses on the download and forgot the upload. Covid seemed to open some eyes. 
I was concerned about VoIP as that's our old home phone (yeah, I've had a cell phone for 35 years, too). Ooma specifically said it works with TMobile. It does. Better than 400MBS cable. I can't speak for Magic Jack. Ooma requires a Telo device (about 80 bucks on Amazon) and the service is "free" (you pay taxes which for me in PA is about 7.25 a month). I had Ooma Premier for several years for robo call blocking and caller-ID with name and free second line. I just dropped it. Same or less robocalls. Uploaded phone book to Oooma so we get everyone we know caller ID name. YMMV. 

Forgot to add---Using the Arcadyn box connected by ethernet to Google Mesh WiFi. I connected the Google Mesh main node by ethernet to a big switch, and my VoIP box is all ethernet to the TMobile box. VoIP really needs ethernet. Ooma even likes you to connect to the cable modem directly (could do that via the second Arcadyn ethernet port but why bother, works great now). 
I've only been on TMobile home internet for a couple months, but it has been perfect so far. My connection is modest at best, no great cell coverage and all the numbers on my phone app are mediocre. However, the service rarely drops below 20MBS down, 3 or so up (usually faster) and I have not noticed any issues streaming or using the phone. I am not a heavy streamer (at all) so my speed needs are pretty low. 
 

I had trouble registering to my SIP provider (voip.ms) when initially connecting my Grandstream DP750 VOIP device to the T-Mobile 5G Home Internet Sagemcom Fast 5688W Gateway.

It worked without any issues when connected through another router, which was downstream from the home internet gateway (double NAT).

After further troubleshooting, I was able to get the Grandstream DP750 VOIP device to register with my SIP provider by selecting the NAT Transversal setting (within the profile I’m using → Network Settings → NAT Settings → NAT Transversal) to the “Keep-Alive” option.

Voice audio is working both directions, and other features seem to be working fine as well (message waiting indicator, etc).

I'm experiencing the same issues trying to use Magic Jack with the black trashcan looking Tmobile router. Just spent an hour with tech support and made no headway. Has anyone figured anything out on this issue?

I just ordered WiFiX NEXPRO V2 5G Gigabit Wireless Internet WiFi6 AX3000 Dual SIM Router with Quectel 5G Wireless Internet Modem.

My friend has it and it gets 1.1 GBPS with his, and his VOIP works through it.  I was gonna go with the cheaper one… but I worry about future compatibility, so went with this.  He's able to disable SIP ALG in the firewall on this.