 Permissive dialing would be allowed because exchange equipment, on detecting a 9 as the second digit of the area code, would respond appropriately to expect 11 digits, or 10 in the absence of a 9 in that position.Under this plan, the New Jersey telephone number 609-555-0175 would become 6909-555-0175.A disadvantage to expanding to 11 digits under this plan is that area codes would continue to be "consumed" at the present rate.