IsPhone(<data>)

This functions uses a number of rules to test if a text string can be accepted as a phone number.

Example:

##CASE(ISPHONE(Phone),1,Phone,SKIPFIELD())

Explanation:

• ISPHONE(Phone)

1. This checks if the Phone field contains a phone number.
2. If it does, the function returns TRUE, otherwise FALSE.

• CASE(condition, value_if_true, value_if_false)

1. It evaluates the ISPHONE(Phone) condition: 
   1. If Phone contains a valid phone number (ISPHONE(Phone) = TRUE), the formula returns 1 and therefore the field is updated with the phone number. 
   2. If Phone does not contain a valid phone number (ISPHONE(Phone) = FALSE), SKIPFIELD() prevents the field from being updated.