Topic Wiki
Topic Wiki
I think there is a big misunderstanding what locked/unlocked means.
All phones that are made are always assigned to a carrier (yes even the ones that say "Factory GSM Unlocked") to prove that just look up the model of the phone and you will see what carrier it was assigned to.
In order for a phone to have service the company has to know that you want service on this phone.
In the past company's like Sprint and Verizon did not work with a sim card they worked with the id of the phone to recognize what kind of phone / what carrier it was assigned to. This is know as CDMA. Yet company's like att/t-mobile did that too but the service was applied by using a sim.
Once LTE came out for what ever reason all company switched to the "Sim technology". There is still one thing that did not change, each carrier has their assigned bands that they have from the FCC that they are allowed to use.
Being that there are standard bands that every one uses (for international or the like) these are included in every phone. So.... All verizon phones will work on att, BUT will only have the bands for slower internet since those are standard bands.
Now verizon's LTE band is NOT a standard nor is their CDMA a standard so an att or a t-mobile phone will NOT be able to accept a Verizon sim.
Now lets go to sprint phones,
All other company's when they had the phones made for them all they do is have it customized for its own use (Read: their own LTE bands). Sprint on the other hand not only did they have them customize it they put a lock in the software blocking all local USA bands (Verizon ATT and Tmobile).
They even go a step farther and they still do the old way of checking the device ID to see if its a sprint phone or not.
Hope this explains a few things feel free to ask any questions.
Att has an easy way to ask for an unlock https://att.com/deviceunlock
How to check a Sprint iPhone (only): You cannot check it with an american sim you must put in a foreign sim. You DO NOT have to backup and restore as sprint sends in the email! Connect to wifi before starting this procedure.
When you put the sim in one of 3 things will happen.
1. It will say no service in the top right corner = Unlocked
2. It will do a soft restart and ask you for your apple id password = Almost unlocked, after putting in the password its unlocked
3. It will do a soft restart and say "Sim not valid" = Phone is locked
If you got number 2. and you dont know the password just put in your old sim and all will return. When you find out the password repeat the steps.
Willmyphonework.net Can check if the phone will work - note old website. Does not seem like it was updated.
All phones that are made are always assigned to a carrier (yes even the ones that say "Factory GSM Unlocked") to prove that just look up the model of the phone and you will see what carrier it was assigned to.
In order for a phone to have service the company has to know that you want service on this phone.
In the past company's like Sprint and Verizon did not work with a sim card they worked with the id of the phone to recognize what kind of phone / what carrier it was assigned to. This is know as CDMA. Yet company's like att/t-mobile did that too but the service was applied by using a sim.
Once LTE came out for what ever reason all company switched to the "Sim technology". There is still one thing that did not change, each carrier has their assigned bands that they have from the FCC that they are allowed to use.
Being that there are standard bands that every one uses (for international or the like) these are included in every phone. So.... All verizon phones will work on att, BUT will only have the bands for slower internet since those are standard bands.
Now verizon's LTE band is NOT a standard nor is their CDMA a standard so an att or a t-mobile phone will NOT be able to accept a Verizon sim.
Now lets go to sprint phones,
All other company's when they had the phones made for them all they do is have it customized for its own use (Read: their own LTE bands). Sprint on the other hand not only did they have them customize it they put a lock in the software blocking all local USA bands (Verizon ATT and Tmobile).
They even go a step farther and they still do the old way of checking the device ID to see if its a sprint phone or not.
Hope this explains a few things feel free to ask any questions.
Att has an easy way to ask for an unlock https://att.com/deviceunlock
How to check a Sprint iPhone (only): You cannot check it with an american sim you must put in a foreign sim. You DO NOT have to backup and restore as sprint sends in the email! Connect to wifi before starting this procedure.
When you put the sim in one of 3 things will happen.
1. It will say no service in the top right corner = Unlocked
2. It will do a soft restart and ask you for your apple id password = Almost unlocked, after putting in the password its unlocked
3. It will do a soft restart and say "Sim not valid" = Phone is locked
If you got number 2. and you dont know the password just put in your old sim and all will return. When you find out the password repeat the steps.
Willmyphonework.net Can check if the phone will work - note old website. Does not seem like it was updated.
« Last edited by jose34 on March 23, 2025, 01:28:26 PM »
