The Public Service Commission ordered Chesapeake & Potomac Telephone Co. yesterday to provide free blocking with its Caller ID service in Maryland, a service that will give callers a way to prevent their numbers from being transmitted to display devices involuntarily.
However, the commission gave C&P no date by which the blocking service had to be offered.
C&P, which had vigorously opposed the imposition of blocking in Maryland, said it plans to fight the commission's decision.
"Our primary objective now is to ask for reconsideration," said Al Burman, a C&P spokesman in Baltimore. "That doesn't imply that we plan to ignore the commission's order [to provide blocking], but I can't give you a date by which that will be accomplished."
Because C&P was still studying the commission's 21-page order as of yesterday afternoon, Mr. Burman said it would be "inappropriate to speculate" when blocking might be offered.
The 4-1 decision by the commission made Maryland one of a handful of states in the United States where per-call blocking is required.
C&P has marketed Caller ID as a consumer service that can be helpful in warding off or tracking down harassing or obscene phone calls.
Critics, however, have faulted the service for intruding upon the privacy of callers, who may or may not want their numbers displayed. Some people who pay for unlisted or unpublished numbers, which show up on Caller ID devices, also considered the transmission of their numbers a breach of contract.
Some people who accidentally dialed homes with Caller ID claimed they were victims of reverse harassment, the PSC noted in its decision yesterday.
Frank Fulton, a PSC spokesman, said the omission of a deadline did not diminish C&P's responsibility to move expediently to make blocking available in Maryland.
"The commission expects C&P to implement blocking as quickly as possible," he said.
The commission's decision calls for C&P to make "per-call" blocking -- a service that allows callers to selectively prevent telephone numbers from being picked up by Caller ID devices -- available free of charge.
Per-call blocking will allow a caller to block transmission of his or her phone number to a Caller ID display screen by hitting a two- or three-digit code (as yet undetermined) before dialing a phone number.
Judith Wolfe, an attorney for House of Ruth, a shelter in Baltimore for abused women, applauded the commission's decision yesterday.
"It's a really incredible step," said Ms. Wolfe, who had argued for blocking before the commission. "It's a recognition that Caller ID threatens privacy not only of abuse victims, but of anybody."
Previously, C&P acknowledged the special needs of such shelters, as well as law enforcement officers and health officials. As a result, C&P now offers free blocking to customers who are approved by the state Department of Human Resources.
Yesterday's decision indicates the commission has since determined that other groups, as well as individuals, may also have a need or desire for protection from the Caller ID service.
In its decision, the commission determined that per-call blocking "remedies the possible negative effects of Caller ID service without sacrificing all the benefits and value of Caller ID. Our decision maintains the availability of Caller ID service while simultaneously recognizing the existence of circumstances in which the calling party should have the option to block disclosure of his telephone number to the called party."
In all, the commission said it had reviewed nearly 1,300 letters from residents and listened to testimony from more than 150 others who showed up at public hearingslast summer before rendering a decision on blocking for Caller ID in the state.
The commission initially approved the introduction of Caller ID -- without blocking -- in Maryland in October 1989. The service costs $6.50 a month per line for residential users, who must also buy a Caller ID device. The device costs about $80.
To date, about 34,000 C&P customers in Maryland subscribe to Caller ID, the PSC said. The service, currently limited to select markets across Maryland, is expected to be available statewide by next fall.