Dual CDMA sims?

[devinpatterson]

I was curious if anyone had tried dual CDMA carriers on their dual sim G4s. My understanding is that for 3G cdma voice the device itself is registered as opposed to a 3G GSM which registers the sim, so only one CDMA service could be active at a time. Changing to another CDMA carrier would mean going through Verizon's or Sprints's activation process each time you wanted to change to a different sim (this was my experience with a 3 sim adapter). I'd love to hear someone more knowledgeable chime in on this subject and provide some feedback on whether or not this is how it would work with a dual sim moto G4.

I'd love to have dual CDMA sims because I have free service with ringplus (Sprint MVNO) but it's spotty in rural areas, whereas Verizon has the most solid signal in the remotest regions.....however I think it's a pipedream. I am aware that you can do a CDMA LTE sim switch and get data without a problem (I'v done this with a triple sim adapter), it's voice and text that I'm interested in being able to switch to, without having to go through the activation process. And because I need this voice and data in remote areas without LTE, VOLTE isn't an option.

I hope that isn't too convoluted or arcane a question, I realize it's not a common scenario. But with the Moto 4G being carrier friendly to all the north american providers (GSM and CDMA) and having a dual sim slot, it's the first plausible solution to what I'd like to achieve.

 

[xtermmin]

Unfortunately, the only G4 models that have CDMA are the US models (XT1644 G4+, XT1625 G4, XT1607 G4 Play, XT1609 G4 Play for Verizon Prepaid), and the US models are only available in single-SIM format.

From what I've been gathering, there are no dual-SIM CDMA phones that fully work with US carriers available yet. The OnePlus 3 comes sorta close, it's dual-SIM and has CDMA Band 0, which Verizon uses in most markets, but at the moment it either works in 1x/EVDO mode for calls/text, or LTE mode for data. However, it's lacking CDMA Band 1 (Verizon & Sprint) and CDMA Band 10 (Sprint), so it's not ideal. It's also lacking Verizon's main LTE Band 13, and all of Sprint's LTE bands.

Slightly good news, though. The upcoming ZTE Axon 7 is dual-SIM and FCC testing indicates that it fully supports all US carriers, including all Verizon and Sprint CDMA bands.

 

[devinpatterson]

Unfortunately, the only G4 models that have CDMA are the US models (XT1644 G4+, XT1625 G4, XT1607 G4 Play, XT1609 G4 Play for Verizon Prepaid), and the US models are only available in single-SIM format.

Ah, that's unfortunate.

The OnePlus 3 comes sorta close,
Slightly good news, though. The upcoming ZTE Axon 7 is dual-SIM and FCC testing indicates that it fully supports all US carriers, including all Verizon and Sprint CDMA bands.

I'll keep an eye on it.

Would the concept work the way I described in the first post though? I'm really curious if the phone would require sprint or verizon activation when switching cdma sims. I don't have a great deal of experience, simply my results with a multisim adapter. I was unable to test the adapter with a verizon and sprint capable phone (like a nexus 6) but tested it with an Verizon samsung s5 using gsm sims and a verizon LTE sim. The gsm sims (various at&t and t-mobile MVNO) were of course no problem, but switching to (or back to) a verizon LTE sim required teh verizon activation process (but not for data, as the LTE was active without activation).

Is it possible to have a dual sim (or even single sim) phone that supports both carriers (Verizon and Sprint) that could switch back and forth, or is the activation process simply inherreient with the way the devices imei's are registered on CDMA networks, and will always be required. For me going through the activation process for Verizon or Sprint when switching sims would simply preclude any practical usefulness with a dual sim cdma capable phone (although it would still have value as a dual sim with a cdma and a gsm sim).

Sorry for the late reply xtermmin and thanks for the info.

 

[xtermmin]

Would the concept work the way I described in the first post though? I'm really curious if the phone would require sprint or verizon activation when switching cdma sims. I don't have a great deal of experience, simply my results with a multisim adapter. I was unable to test the adapter with a verizon and sprint capable phone (like a nexus 6) but tested it with an Verizon samsung s5 using gsm sims and a verizon LTE sim. The gsm sims (various at&t and t-mobile MVNO) were of course no problem, but switching to (or back to) a verizon LTE sim required teh verizon activation process (but not for data, as the LTE was active without activation).

Is it possible to have a dual sim (or even single sim) phone that supports both carriers (Verizon and Sprint) that could switch back and forth, or is the activation process simply inherreient with the way the devices imei's are registered on CDMA networks, and will always be required. For me going through the activation process for Verizon or Sprint when switching sims would simply preclude any practical usefulness with a dual sim cdma capable phone (although it would still have value as a dual sim with a cdma and a gsm sim).

Sorry for the late reply xtermmin and thanks for the info.

I can't speak for Sprint, as I have Verizon, but I do know that they're more restrictive than Verizon.

On Verizon, the only current restriction is a whitelist when you try to activate a SIM for the first time. You have to use a device that's in Verizon's "activation database", typically Verizon-branded devices, iPhones 6 and up, the Moto X Pure, and (at some point, if not now) the Moto G4 lineup. Once you have an activated SIM, you can stick it into any compatible device (be it from Verizon, another provider's phone, or even an unlocked phone that doesn't officially work on Verizon) and you should be good to go.

For example, I've been using my same Verizon SIM that I got with the HTC Thunderbolt (when it launched in March 2011) in numerous other phones (Verizon phones, US Cellular phones, unlocked phones, even some GSM/LTE-only phones) with no need to contact Verizon or use the website or anything. I've been able to just pop in the SIM, adjust the connection method on the phone if needed, and go.

As for your experience with using a dual-SIM adapter on the Verizon GS5, it might be due to the phone going into "GSM/LTE" mode when you insert a ATT/TMO SIM, but not switching to "CDMA/LTE" mode when you switch to your Verizon SIM (thereby only connecting in LTE mode). Might want to try setting it to Global mode (GSM/CDMA/LTE). The Verizon version probably wasn't tested for dual-SIM use, so it might just be the OS not knowing to switch to the other mode, or it might be an issue with the adapter itself.

Regarding an actual dual-SIM device with both SIMs being CDMA, I'm unsure if it causes any issues, as there's been no phone with that ability released yet (technically, someone can try dual Verizon SIMs in the OP3, but the CDMA implementation on that phone looks to be pretty half-assed, so I wouldn't use it as a baseline). Guess it depends on how the SIM slots are setup (if they share the same IMEI, or if they have different IMEIs for the two slots). If they're the same IMEI, I can see there potentially being issues, but if they're different (which should be the case for any modern name-brand flagship), there shouldn't be.

We'll know more once the Axon 7 releases. Unfortunately, ZTE has said that CDMA support will be coming in a software update later, but at least the phone is physically banded for CDMA, so we won't know for sure until then.

 

[coliotte]

Actually the xt1644 have dual sim slots , one is hidden open the phone and you will find it