Hi @deepakt1812
If the only functionality that you are trying to get by using a telephone field is the number pad pop up on mobile, have you tried setting the following field under basic settings for the "Numeric Box" component?
If the "Numeric Box" still doesn't work as required, you could also create a custom widget based on the numeric box and extended it.
If you still want to use the telephone field for other reasons, then you should make sure it works as you expect by testing thoroughly. If you are using AEM 6.3, you could write test cases using calvin to:
* check alpha characters are rejected,
* the comparison functionality in your other post works
* ensure numbers are handled etc.
It will also help if you decide to swap the component for a different one later as well as the tests will prove that it works.
A good tutorial for automated testing Adobe Experience Manager Help | Using Automated Tests with AEM Adaptive Forms
The downside of using the telephone field will be handling minimum/maximum values that the numeric field handles.
Thanks,
James