New Phone not Connecting to T-mobile Network

Naffanaffa wrote:

Thank you so much for the guidance so far, I have learned a lot from this! The shop owner told me I can replace the phone with either KYOCERA KYF37 GRATINA2 4G WIFI KEITAI, o KYOCERA KYF31 GRATINA 4G WIFI KEITAI. He said they are compatible with Sprint’s bands for 4G 26 and 41(main is 25, but phone does not support band 25). so 2/3 bands compatible, excluding main one. Before I proceed with the replacement. Will they work if I buy a SIM/plan with Sprint with decent coverage?

Here’s what I could find:

KYF37

• 2G Network : GSM EDGE 850, 900, 1800, 1900 MHz.
• 3G Network : UMTS HSDPA UMTS 850, 1900, 2100 MHz.
• 4G Network : FDD-LTE 700, 800, 850, 1800, 2100 (Band 1, 3, 17, 26)
• 4G Network : TD-LTE 2500 (Band 41)

KYF31

• 2G Network : GSM EDGE 850, 900, 1800, 1900 MHz
• 3G Network : UMTS HSDPA UMTS 850, 1900, 2100 MHz
• 4G Network : FDD-LTE 700, 850, 1800 (Band 3, 17, 26)
• 4G Network : TD-LTE 2500 (Band 41)

Of the 4G bands listed, T-Mobile uses only band 41, for very short range urban coverage. I'm not even sure it supports voice calling. Here's the issue: All the big carriers are dropping support for 2G & 3G.  4G LTE will be the new baseline for wireless phones, with 5G NR rapidly taking first place. AT&T has dropped 2G and is dropping 3G in many markets. Verizon keeps putting off CDMA 2G & 3G sunset but the threat is constantly being repeated. T-Mobile has killed 3G in most urban areas and is warning about its general demise. They run a very thin 2G signal in some places to support old wireless alarm systems. I personally would like to be able to continue to use my old 2G & 3G phones but the customers' demand for bandwidth is simply insatiable, so the carriers must deploy only the most efficient technologies. 

Any phone you buy today needs LTE bands 2, 4, 5, 12 & 71 at a minimum and bands 25, 41 & 66 are good to have. You also need Voice over LTE (VoLTE) . These Kyocera phones simply will not work with T-Mobile. I'm not sure who they were manufactured for but the band selection is strange. Band 17 indicates AT&T and band 26 says Sprint. If it had been for Sprint it would have included band 25 and CDMA. I'm sorry to be the bearer of bad news but that's how I see it.

Sprint is absobed by T-Mobile. Due to agreements with DOJ and FCC some markets T-Mobile will lose Sprint coverage.  Also I believe you can no longer get any Sprint plans and their website will take you to T-Mobile.  If they still do then my guess they haven't fully switched everything over.  It's the same rates and coverage going forward however.

drnewcomb wrote:

Naffanaffa wrote:

Do you know any carrier I can use that is compatible with the phone’s 4g?

In the USA? No. It’s not on AT&T’s whitelist, so they won't allow it. It doesn't have band 13 for use on Verizon. T-Mobile's the most permissive carrier about accepting BYODs.

Thank you so much for the guidance so far, I have learned a lot from this! The shop owner told me I can replace the phone with either KYOCERA KYF37 GRATINA2 4G WIFI KEITAI, o KYOCERA KYF31 GRATINA 4G WIFI KEITAI. He said they are compatible with Sprint’s bands for 4G 26 and 41(main is 25, but phone does not support band 25). so 2/3 bands compatible, excluding main one. Before I proceed with the replacement. Will they work if I buy a SIM/plan with Sprint with decent coverage?

Naffanaffa wrote:

Do you know any carrier I can use that is compatible with the phone’s 4g?

In the USA? No. It’s not on AT&T’s whitelist, so they won't allow it. It doesn't have band 13 for use on Verizon. T-Mobile's the most permissive carrier about accepting BYODs.

drnewcomb wrote:

One thing that crossed my mind is that there might be a setting somewhere under "Network" that looks like VoLTE/LTE Voice/4G Voice/etc. If this is turned off it could cause the symptom you're describing. In any event, with only one 4G band for T-Mobile, it's not a good choice.

Do you know any carrier I can use that is compatible with the phone’s 4g?

Do you know any carrier I can use that is compatible with the phone’s 4g?

One thing that crossed my mind is that there might be a setting somewhere under "Network" that looks like VoLTE/LTE Voice/4G Voice/etc. If this is turned off it could cause the symptom you're describing. In any event, with only one 4G band for T-Mobile, it's not a good choice.

drnewcomb wrote:

Naffanaffa wrote:

I finally found the FCC ID, it is JOYYKEA60

That's it. Unfortunately the test data submitted to the FCC is not very revealing and the user manual submitted with the test is almost entirely in Japanese and contains no information I could use to help you. I can't see how you can lock the phone in GSM mode to test if that will work.

You shouldn't buy a phone based on wishful thinking. There are too many ways for them to not work or work poorly. There was a time when I only bought unlocked phones from overseas. That was then, this is now. Our current two main phones came from T-Mobile and the backups are types known to work with T-Mobile before they were purchased.

thank you for your help and effort. I will try and see if I can return the phone, or get a replacement for a phone that works with t-mobile.

Naffanaffa wrote:

I finally found the FCC ID, it is JOYYKEA60

That's it. Unfortunately the test data submitted to the FCC is not very revealing and the user manual submitted with the test is almost entirely in Japanese and contains no information I could use to help you. I can't see how you can lock the phone in GSM mode to test if that will work.

You shouldn't buy a phone based on wishful thinking. There are too many ways for them to not work or work poorly. There was a time when I only bought unlocked phones from overseas. That was then, this is now. Our current two main phones came from T-Mobile and the backups are types known to work with T-Mobile before they were purchased.

drnewcomb wrote:

Naffanaffa wrote:

I bought it as T-mobile's main band for LTE is 4, which the phone supports. SO it is supposed to work, right? 

 

The phone also has to support T-Mobile's VoLTE system which is not stated in the specs I saw. Unfortunately compatibility of BYODs is entirely the responsibility of the customer. Maybe if you could provide the FCC ID of the phone I could research it some more. The FCC ID is an alphanumeric code about 7-9 digits long like "R7BJ6U43". It's found either on a sticker or in the Govt Info page in Settings menu.

I finally found the FCC ID, it is JOYYKEA60