The Kentucky Public Service Commission on Friday revised the starting date for the optional use of area code 364, delaying it by six months to Jan. 1, 2009.

The change reflects an updated estimate of the date by which the present area code, 270 – from which area code 364 will be split – will run out of available numbers.

In an order issued Friday, the PSC also continued to hold open the date for mandatory use of area code 364. It will not be determined until after the PSC fully assesses how a Federal Communications Commission decision regarding the assignment of telephone numbers will further affect the lifespan of area code 270.

Area code 364 will cover the western portion of the current area code 270, including the cities of Henderson, Hopkinsville, Madisonville, Murray and Paducah.

On May 31, the PSC decided to accommodate the rising demand for new telephone numbers in western Kentucky by splitting area code 270, with the eastern portion retaining the current area code. Cities remaining in area code 270 include Bowling Green, Columbia, Glasgow, Elizabethtown and Owensboro.

The North American Numbering Plan Administrator, which allocates telephone numbers to telecommunication providers, recently revised its estimate of the number exhaustion date for code 270, from the fourth quarter of 2008 to the first quarter of 2009.

On the same day that the PSC issued its order splitting area code 270, the FCC granted the PSC’s request for a change in the way telephone numbers are allocated by NANPA within the area code. The FCC decision, which allows the PSC to require a procedure known as “number pooling,” could free up thousands of unused telephone numbers.