Every supplier's SIM is different (yet another phone complication)

[A Dude]

[I am now beginning to see why people just pick AT&T or Verizon and signup for postpaid. Otherwise, all the details are even too complicated to nerds like myself.]

So, I have an older Samsung phone, unlocked GSM with LTE. I live in the U.S.

I have been using a Truphone SIM in it, and oddly enough, despite it being a SIM from overseas, everything is far simpler than what I have been trying lately. It roams on the AT&T. Network Cell info app says "4G LTE".

I happened to have an unused T-Mobile SIM that was never used (for a family member who changed their mind). When I insert this SIM, the Network Cell Info app says "4G LTE".

I ordered a Lycamobile SIM from ebay for 99 cents, hours before reading that Lycamobile was discontinuing Paygo. When I inserted their SIM (just to see what happened), the Network Cell Info app says "3G UTMS". Apparently, T-Mobile does not let them do LTE.

I also ordered a PagePlus SIM from ebay for 99 cents, just so that I could check Verizon 4G signal strength here. The SIM refuses to even connect. I am guessing this has something to do with Verizon approving each individual phone that connects to their network, although I am surprised this apparently applies to even SIMs that are not activated. If I cannot measure signal strength before buying a phone, it's hard to justify doing that.

-----

I have another phone, which is a flip phone which is a spare phone, and has LTE bands for Sprint. When I enter the IMEI at the Tello web site, they tell me it won't work on their Sprint network. But the phone's bands support Sprint for 2G, 3G and 4G:

LTE 4G
band 25 / 1900 MHz PCS+G (USA (Sprint))
band 26 / 850 MHz Extended Cellular (USA (Sprint))
band 41 / 2500 MHz BRS / EBS (USA (Sprint))

WCDMA 3G / 4G
band 1 (I) / 2100 MHz IMT (Europe, Asia, Africa, Oceania, Brazil, India, Israel)
band 2 (II) / 1900 MHz PCS (Americas)
band 4 (IV) / 1700 MHz AWS (Americas)
band 5 (V) / 850 MHz Cellular (Americas, Oceania, Brazil, Israel)

CDMA 2G / 3G
band 27 / BC10 / 800 MHz ESMR (Americas (Sprint))
band 5 / BC0 / 850 MHz Cellular (Americas, Oceania, Brazil, Israel)
band 2 / BC1 / 1900 MHz PCS (Americas)

GSM 2G
band 5 / 850 MHz Cellular (Americas, Oceania, Brazil, Israel)
band 8 / 900 MHz (Europe, Asia, Africa)
band 3 / 1800 MHz DCS (Europe, Asia, Africa)
band 2 / 1900 MHz PCS (Americas)

This flip phone works fine with a Piranha SIM that roams on AT&T, and when the Lycamobile SIM is inserted, it even reports "Lycamobile" despite the SIM not being activated.

Apparently, to even try out Verizon or Sprint, you have to buy a phone directly from them or their MVNOs.

All of this is too complicated - because - there are no standards. Internet has standards used by everyone - TCP/IP, DNS, HTTP, etc. TV has standards used by everyone - ATSC, MPEG2/4, etc.

[hyelton]

But what is your phone model? That plays a HUGE ROLL in what your trying to do....


My unlocked iPhone XS works perfectly fine on Sprint, AT&T , T-Mobile, Verizon etc etc.

A typical gsm unlocked device is NOT going to work on cdma networks like Verizon or sprint.


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[clonehappy]

It's really not complicated at all.

Just make sure you use known compatible phones. This means: iPhones, most Moto phones, flagship Samsung or LG.

I've never had to buy a phone from Verizon or Sprint to use their service either branded or through an MVNO. But I own phones that are compatible with their services, so I don't have to play games to get things to work.

Also, Lyca definitely has 4G LTE. Even on their now-supposedly-but-not-really discontinued PAYG, I get VoLTE.

As for Verizon/Verizon MVNOs, you have to activate the SIM using a compatible IMEI (compatible, doesn't mean you had to buy it from them) and then you can use it in any device that has the right bands.

Sprint and their MVNOs require the correct model of SIM, which there seems to be hundreds of, and it has to be paired with the device so no swapping after it's activated.

Sure, branded T-Mobile or AT&T are the easiest, because it'll generally just work in any old phone. But having a compatible phone solves that problem, too.

So, yeah. Like the last guy said, what phone are we talking about here anyway? Maybe we can help.


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[A Dude]

Thanks, but you verified my point - that each network has a different type of requirement for either phone or SIM or both.

It's four walled gardens.

[A Dude]

If Lyca does have 4G LTE on the same T-Mobile network, then the most likely candidate is that T-Mobile does not allow T-Mobile MVNOs to access the T-Mobile 4G LTE Signal Booster, so the phone drops back to 3G when the Lyca SIM is inserted. So we can add that to the list:

* Is the phone compatible ?
* Is the SIM compatible ?
* Is VoLTE supported ?
* Is domestic roaming supported ?
* Is there a local tower ?
* Is it allowed on the Signal Booster ?

Although everything is getting more complex, I think phones have the most complexity for a consumer device.

[djphilosophy]

SIM cards don't have requirements other than being the same size used by your phone: mini SIM, micro SIM, nano SIM.

Service providers may implement limitations, i.e. not allowing you on LTE for a prepaid (budget) service.

Service providers also require a compatible device, and you have two historically different wireless technologies: AT&T and T-Mobile coming from GSM, Verizon and Sprint coming from CDMA. All are using LTE now, but for backward compatibility reasons you need a device that's either GSM-compatible or CDMA-compatible -- or both, which is relatively rare and typically limited to flagship devices like the more recent iPhones. Beyond that, there are a huge number of LTE radio frequency bands used throughout the world (you can't just have everyone using the same frequency, plus different frequencies are ideal in different situations), and to use any given provider you need to make sure your phone supports their LTE bands. Higher end phones tend to support many (i.e. you'd get LTE service almost anywhere in the world). Budget, carrier-branded phones tend to support only the LTE bands used by that carrier or within that geographical region (Europe, Asia, the Americas - but outside the US is another topic). In the US you have crossover, e.g. AT&T and T-Mobile devices tend to be compatible on each other's networks. If you want to keep things more simple, focus on compatibility with those two.

If you buy a device through a provider, it's likely locked to that provider, and thus you'll get an error if you put a T-Mobile SIM in an AT&T-branded device.

I'm not sure what you're actually trying to do with this post. If you're here to complain that this is "too complicated", which is just saying you don't understand how things work, I don't expect you'll get much help. If you're here to learn, quit complaining and ask the right questions (after you've done web searches on those questions).

[Boz1]

Lycamobile paygo had NEVER had data since they discontinued their original SIM cards in the US.

[whacker]

Seems like you ventured into this area expecting things that shouldn't have been expected.

Your as yet model-unknown Samsung phone might have the radio band capability for LTE on AT&T, but inserting an unactivated SIM in a device won't necessarily give you the quantifiable results an activated one would.

[A Dude]

SIM cards don't have requirements other than being the same size used by your phone: mini SIM, micro SIM, nano SIM.

Not according to Tello, who are a member of Howard Forums and wrote:

GSM SIM cards can be swapped indeed between different phones, but this is not the case for CDMA unlocked Sprint devices, which need specific SIM cards. Even if the SIM size is the same for both of the phones, the Moto and LG will require different SIM types. Tello does not tie the SIM card to the phone, it is simply a requirement of the CDMA service.

[hyelton]

Not according to Tello, who are a member of Howard Forums and wrote:

It only applies for Sprint though


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