Handsets of Vtech Doorbell IS7121 Either out of range

Anybody can help solve this issue?

Cordless phones means a finite life of rechargeable batteries even when left in their charging cradles. This may be worn out batteries if electronics haven't failed outright.

Thanks F Dryer for your feedback and comments. I’m looking for a code to reset the handsets of the vtech IS7121-2, I saw such a reset code (s) to reset different handsets of other vtech models. Like *7890# and *331734* or *331734#. None of which worked.

I'm not familiar with vtech so I'm guessing on a reset; removing the battery to each handset, wait about a minute so memory is erased (unless memory is kept alive with a button cell battery). If you're not concerned about preset memories for phone numbers, removing both batteries (if there's a button cell to retain phone numbers, should result in a hard reset back to factory settings. Your manual should have instructions for setting up the phones as if new.

I do thank Mr. dryer for his support and help resolving the issue.

I fact, I could rest the handsets by entering the code using the handset keys; as follows:

*331734# and upper left key for intercom or back space. It worked perfectly.