Activating an ancient (GSM?) Nokia 2190 phone on AT&T

I have an ancient, Nokia 2190 phone on "Sprint". I am trying to get it to work with AT&T.

Yes, I am pretty sure this phone is GSM, and not CDMA:

This was "Old Sprint", which ran a GSM network. more recently, they switched to CDMA. Please don’t say otherwise unless you know what you’re talking about.

Model number: 2190 (NOT the 2190-e model, which isn’t GSM)
Type: NHB-2ND

This is the 1900 Mhz version of the 2110 for the North American market.

I am trying to use this phone on AT&T, however I get an error message: "SIM CARD REJECTED". I believe that AT&T in the US supports 1900 band, and I also believe this phone is 1900 band.

I believe I already unlocked the phone. The phone had an old, (Sprint PCS?) SIM card already inserted. Inserting an AT&T SIM card caused the phone to say a message about wrong type of SIM card. This page had an old DOS program, nsl exe, I used to generate the unlock code to unlock the phone:

Now, when an AT&T SIM Card is inserted, the phone turns on and doesn’t say anything about invalid SIM. However after it fully boots up, the phone eventually says "SIM CARD REJECTED". Any ideas how to get it working?

I tried it with several different AT&T SIMs, and a T-mobile SIM, and got this message. The ancient SIM card it came with doesn’t get this SIM CARD REJECTED message.

My best guess, is either:

  • I didn’t unlock the phone properly
  • There is some setting /proramming on the phone that needs to be changed
  • there’s something wrong with the AT&T sim cards, they’re 3v and need to be 5v….?
  • some other incompatibility with the SIM card i inserted

Any input would be helpful. I want to get this phone working for fun, not as a regular phone to be used.