"It's a discretionary service. We want to encourage customers to use the telephone book," said Lillian McGee, a spokeswoman for Verizon.

This will be the third increase over the past four years. The price for assistance calls beyond the free ones was 50 cents in 2003.

Business customers stopped receiving free directory assistance calls in 2003. The rate for each 411 call for those customers remains at $1.25.

The monthly charge for a non-published number for both businesses and residences will rise to $4 per line, up from the current rate of $3.50.