Prefix overview
Phone numbers in prefix 231-399
This page covers the 231-399 prefix in the United States. It shows where numbers come from, which carrier is linked to the range, and how this block is structured.
If you are looking for a specific number, you can continue to its dedicated phone page. Otherwise, this page helps you understand the broader number block behind it.
PREFIX
231-399
RATE CENTER
FRANKFORT
CARRIER
ACD TELECOM, INC. - MI
MI
Prefix range
The prefix 231-399 includes numbers from 2313990000 to 2313999999.
This range is associated with the FRANKFORT rate center and was originally assigned to ACD TELECOM, INC. - MI.
Numbers in this prefix
20 numbers