The overlay transition is expected to occur first through a "permissive" period, during which customers would be able to dial either seven or 10 digits for local calls. A "mandatory" period would follow, and callers trying to use only seven digits for a local call would get a recording reminding them to dial the area code first.

The new area code implementation was first ordered in 2000, but number-conservation measures postponed its activation. At a technical conference in April, the commission said that new phone numbers are expected to exhaust the 801 area code by June 2008.

Telecom companies preferred the overlay method in 2000, but the commission found it "unacceptable," citing several reasons but saying it was "primarily concerned with minimizing the impact on the general populace." People attending four public hearings that year voiced support for the split.

But telecom representatives in April said customer habits and preferences had changed since 2000 and that a split would be confusing and costly to customers having to switch to the 385 code. In particular, small businesses with a new area code could be hurt as customers try to call them with the old area code, they said.

The telecom reps also noted at the time that burglar and fire alarm companies would need early notification if an overlay were used because some still program systems using seven-digit numbers. Telephone directory companies are expected to begin listing numbers in a 10-digit format.

---

E-mail: bwallace@desnews.com