Tello Plans to Convert to GSM

Tello announced recently that they plan to convert to GSM by "the end of the year". Tello said if you have a CDMA only phone you will need to get a new phone that is GSM. They also said there would be a faze-in period to give CDMA customers until June of 2021 to switch over.

Could be a great thing for many folks depending upon which GSM network they use & how it may affect their pricing.

This, I am looking forward to! I will take them in heartbeat either with AT&T or T-Mobile provided their customer service remains solid. I just hope that their rates remain close to the same if they do have to make adjustments. This does makes me think about the people that I referred to that may not have a clue that this is taking place. Thankfully, those people had carrier agnostic phones then, so AT&T or T-Mobile will work. Looks like I will have some work to do to help out those folks.

Please see this earlier thread for more information:

Don't all CDMA phones have GSM radios? Thereby making it possible to use a GSM SIMcard in a CDMA phone?

Not all CDMA phones have sim cards.

The first hurdle to get over here is a SIM lock. (For example, phones that are locked to Sprint or Verizon networks.)

The second hurdle is software radio blocks. (I think the 2nd Gen Moto E referenced in the other thread had this issue, but fortunately a user-initiated process to bypass the block.)

The third hurdle is band support, which may be the same or different than software radio blocks. (LG, for example, seemed to make a lot of custom variants for different networks that simply did not include band support outside of the branded carrier.)

The fourth hurdle is whether the phone supports features needed by other networks. (Examples would be T-Mobile or Verizon VoLTE certification.)

The newer a phone is, the better the chance that some of the hurdles might be manageable. There seems to be considerable consumer hope that T-Mobile will clear the first hurdle for Sprint-network locked phones as part of the transition-- but I haven't seen much indication that this will be true for older phones, and it's likely to be irrelevant if the other hurdles are still barriers.

I read somewhere that sprint phones work woth tmobile sims now (assuming they are compatible). Haven't tried it though. If true no need to worry about unlocking.

I think that would be the first hurdle I mentioned: SIM locking. That does seem quite easy for new T-Mobile to allow, if they're inclined. It might take a profile update to enable it? I don't know the exact process.

I'd certainly give it a try, but I don't think I have any devices here that have that as the only hurdle. I do have have a couple that are both SIM-locked and have software radio blocks. I doubt T-Mobile is going to do anything to fix those.

  1. Old CDMA phones (even those supporting LTE) do not have SIM card slot.
  2. Some CDMA/LTE phones do not support GSM (and T-Mobile's VoLTE).
  3. Some CDMA/LTE phones have GSM radio but it is locked forever and can not be used.
  4. Some CDMA/LTE phones (for example ZTE Prestige 2) have GSM radio that can be unlocked using some kind of hacking. But these phones do not support T-Mobile's VoLTE and their usage is very limited on T-Mobile network.
  5. Some CDMA/LTE phones have GSM radio that can be unlocked easy (using unlock code request). But these phones do not support T-Mobile's VoLTE and their usage is very limited on T-Mobile network.
  6. Only Sprint branded iPhones, latest Samsungs, some LGs (and may be few other models) can be used on T-Mobile network without problems.

Really? LTE handset without SIM card? Are you sure you are not referring to certain WiMax handsets?

Can you given an example?

re: 1 : Some of the first-generation Sprint LTE phones used embedded SIMs: They had a SIM chip but you couldn't remove it or change it. The LG Mach was such a model.

  1. The semantics get tricky on this one. A number of phones had software locks on GSM radios-- including the LG Tribute HD, which was designed as a 'world' phone but had bands crippled by Sprint.. Many times (usually? always?) the software block could be removed via 3rd party vendors, but would never be unlocked by Sprint. The Verizon Moto E 2nd generation was a similar situation, although there was a do-it-yourself solution for at least the early OS version. I'm not sure whether the GSM radios got unlocked when Verizon provided unlocking. (The question was always whether there was enough demand for someone to develop a workaround to enable the radios.)

Thank you very much, @KentE and @idanth.

I have much to learn!

Three other models off the top of my head that had LTE and no SIM on Sprint:

  • HTC Evo LTE
  • Samsung Galaxy S3 (L710)
  • Samsung Galaxy S4 (L720) (I think)

I know the S4 had a re-release as a tri-band model (L720T) that did have a SIM slot, and the S3 for some reason had a limited run of the L710T (a tri-band S3) that has a SIM slot as well.

LG Viper has LTE on Sprint & no removable SIM.

ZTE Jasper has LTE on Sprint & no removable SIM too.

Tello will soon activate new customers on T-Mobile only.

"Tello Mobile has provided further details about its planned transition over to the T-Mobile network. The transition is now planned for the week of November 22nd. Upon completion of that transition, all new customers will be activated on the T-Mobile network. Activations on Sprint will no longer be an option. Tello's current rate plans will remain in place."

That is a blow to my emergency backup plan of activating my Sprint phone(s) on Tello's $8/mo unlimited T&T plan. The advantage was that I wouldn't have to wait for a SIM to be shipped out to me.

From what I gather, TMobile SIMs have expiration dates and need to be activated within 45 days of purchase - which means I can't just buy a SIM today and put it in the drawer to be used in an emergency.

Anyone have any ideas on a low-cost provider whose SIM I can buy and put in a drawer for emergency use?

Are you familiar with the "Truphone" $30 with $15 credit sim on the AT&T network. I've had one for several years and one need only to make a call every six months (I make a call once a month to be sure)or so to keep it active, so one can keep it in a drawer. It's Paygo.

And with Truphone ALL incoming calls and texts are FREE. Outgoing are 9 cents a min/text P.S. Outgoing can be as low as 1 cent a min with a cleaver workaround.