My Uniden handset cordless phone says in window: Ringer off and I cannot change it to Ringer ON

SOURCE: change ringer from lo to hi

Do you know the model #? If so, you can get the owners manual from the the uniden website. Here is a link to the page so you can look for your specific model number. Just click on your model number and it will load the pdf format of the owners manual.

http://www.uniden.com/index/manuals_results.cfm?cat=1

SOURCE: UNIDEN 5.8 GHZ CORDLESS PHONES

Registering Handsets to the Base
Whichever handset you choose to charge in the base is automatically
registered to the base. Any additional handsets must also be registered to
the base before you can use them.
Be sure both handsets are fully charged.
One at a time, place each handset in the base. The charge/in use LED on
the base begins to flash, indicating the base is registering the handset.
Wait for at least five seconds, then pick up the handset and press
[talk/flash]. If the display shows TALK, the handset is registered. If not,
place the handset in the base to try again.
Press [end] and continue with the next handset.
Note:
Once both handsets are registered, it doesn’t matter which
handset is placed in the base or the charger.
When you charge the handsets, Caller
ID summary screen and the name of
the handset appears.

This can be find from uniden website.
http://www.uniden.com/pdf/DXAI4588-2om.pdf

SOURCE: Uniden 5.8 GHz Digital cordless w 3 handsets interference background noise no matter where we are in the house or which handset we use

This is possibly caused by the internet connection.
Try new ADSL filter.
You need one each per device.

SOURCE: Continuous Flash of Visual Ringer(Uniden DECT 6.0 Cordless)

UNIDEN MODEL EZX290 HANDSET>>>VISUAL RINGET AT TOP (YELLOW LED) FLASHES. HOW DO I TURN THT OFF?

SOURCE: the visual ringer keeps flashing on my uniden cordless phone

I CALLED UNIDEN WITH THE SAME PROBLEM.

THE VISUAL RINGER IS FLASHING WHEN YOU HAVE OLD EMAILS. YOU HAVE TO DELETE THE OLD EMAILS