The model is part of the Base Band 5 series phones, which are more difficult to unlock compared to previous Nokia phones.
Features include a 1.3-megapixel digital camera, support for up to a two-gigabyte microSD Card, 240x320 QVGA screen with 16.7 million colors and external 128x160 TFT screen with 262,144 colors. Software includes an XHTML compatible web browser, an email client and a media player (mp3, mp4 (audio only) & 3GP supported). There is also a small button located on the top right side of the phone, that when pushed, flips the phone open.
The phone is very customizable. Users can manage many of the phones features in the Nokia PC Suite. Themes may also be downloaded onto the phone, changing the menus, icons, colors, etc. Other customizable aspects of the Nokia 6126 include adding MP3 files to the phone, and using those files as ringtones, without the need of converting them to WMA format. There is also a setting used for the screen saver on the external screen of the phone that allows a slide show of images the user has taken with the phones camera.
- 6126: North American version of the 6131 (released for AT&T and Fido Solutions)
- 6131: has additional features of a FM receiver and IrDA connectivity
- 6131 NFC: includes Near Field Communication. First phone ever produced with NFC capability.
- 6133: has a silver keypad (vs black in the 6126/6131 models), a FM receiver, and a slightly different arrangement of camera lens and external LCD screen compared to the 6126 and 6131. Only signed Java ME applications are allowed access to the network stack, with no option to change it. (released for T-Mobile)
"Sent Items" mailbox problem
There is/was a problem with the sent mailbox in the text messaging system which involved the messages not opening. Instead of displaying the mailbox, the system displays message that the operation was failed.
The 6126, 6131, and the 6133 have been known to have some problems with the sending of MMS messages. Typically, when trying to insert a picture in the message, the screen fades out with black bars, and then to a white screen and the phone returns to main screen (often known as restart). No real explanation as to why this happens has surfaced. There are various ways of fixing this problem though. Doing a full reset of the phone and not messing with the MMS settings is one. Users have been able to send messages after this, although for some, the problem arises again. Some users report that disabling message delivery reports fixes the issue. Unlocking the phone is another option. This can usually be done by shipping phone off to an unlocking website or a service center and having the service performed for a fee.