I use Google Voice as my outward-facing number: I place calls via carrier service, but displaying my Google Voice #, and my Google Voice # is the number people call me on.
Recently, something has changed. My SO is on Tello/Sprint (and does not use Google Voice). When I call her phone, I don't currently hear it ring. If I hold on and wait, she'll either answer or I get directed to voicemail, but until either of those happens, it's silent. It's really inconvenient, because I'm not sure the call is actually going through, or Google Voice has failed, or ....
I took the time to investigate last night, with a selection of phones. Results:
When calling from my Google Voice #, installed on a Tello/Sprint phone.:
Tello/Sprint does not ring (but is connected.)
Tello/T-Mobile does not ring, but is connected.
Red Pocket/CDMAS(Sprint) does not ring, but is connected. (So it's not specific to Tello.)
FreeUP AT&T does ring.
Tracfone Verizon does ring.
I repeated the tests using the native cellular number from the Tello/Sprint phone instead of using my Google Voice #. I hear rings for all the outgoing calls above.
I repeated the test using the same Google Voice #, installed on a FreeUP/AT&T phone. Exactly the same results as the list above: so it's not specific to the carrier I'm using to place the calls using my Google Voice #. If I call using my native FreeUP/AT&T number, everything rings. (Same results testing with 2 different underlying carriers for outgoing calls.).
I repeated the test using a different Google Voice #, installed on the Red Pocket/CDMAS phone. The ringing/no ringing results match the first examples, so it's not specific to my usual Google Voice #-- it happens with 2 different Google Voice numbers.
So, this problem seems to be a consistent one when calling from a Google Voice number to either legacy Sprint or T-Mobile lines. My understanding is that the ring tones we hear when waiting for a phone to be answered are 'spoofed' on the calling line, and are created when a particular code is sent from the network handling the receiving end of the call once the circuit switches to the called number are in place.. (I'm not sure about all the details of how this works.) If that's correct, something is broken between Sprint/T-Mobile sending the "connected" code, Google Voice receiving it, and Google Voice "spoofing" the ring tone.
I'm wondering if anyone else is seeing this symptom? I'm also curious if it's similar when calling via VoIP providers in general. (Maybe TextNow? But I only have a semi-functional TextNow line, and haven't had time to test yet.) I'm likewise curious if it's a result of something T-Mobile is doing regarding spam filtering-- but the calls aren't blocked, it's just the missing ring tone.
(Just realized I didn't try calling via my Google Voice # over WiFi. Guess I'll have to gather the phones again...)