GE 26958 User Manual page 68

Available formats include:
Number of digits
Eleven digits
Ten digits
Seven digits
NOTE: If the phone company does not supply all ten digits of an incoming
caller's number, you will not be allowed to adjust the format of that number.
68
Explanation
long distance code "1"
+ 3-digit area code
+ 7-digit telephone number.
3-digit area code +
7-digit telephone number.
7-digit telephone number.
Example
1-317-888-8888
317-888-8888
888-8888