Chesapeake & Potomac Telephone Co. now wants to do for businesses with centrex systems what it does for residential customers: Give them a way to peek at the numbers of incoming calls.
Under a C&P plan submitted to the Public Service Commission last week, any business with three or more lines could buy Caller ID.
The controversial service, which permits users to obtain the numbers of incoming calls, has been available in Maryland since October 1989.
To avoid detection by Caller ID, callers must dial the code "star-6-7" before placing a call.
This blocking feature, also offered by C&P, is free.
To date, Caller ID has largely been marketed and sold as a service for residential and small business customers.
It has also been available to large businesses with PBX switchboards on a special-order basis.
But the service hasn't been widely available to C&P's 11,000 business customers with centrex, which are large-scale telecommunications systems that can handle anywhere from three to 10,000 or more telephone lines.
According to last week's filing, which C&P wants to take effect Aug. 14, C&P plans to charge centrex customers on a sliding scale: Customers with one to 10 lines will pay $6.50 per line; customers with 11 to 50 lines will pay $5 a line; and those with 50 or more lines will pay $2 per line.
Residential customers pay $6.50 per line.
People's Counsel John Glynn, who represents the interests of residential customers before the commission, said that he doesn't understand why C&P plans to charge some businesses less than a third of what it charges consumers for the same Caller ID service.
"I don't know what it is about the number of lines one has that makes it any cheaper to provide the service," Mr. Glynn said. "This raises a question that has to be clarified or brought to the attention of the commission."
Al Burman, a C&P spokesman, said the Caller ID rate for business customers is based on "their willingness to pay. Obviously, it's not cost effective to them to pay $6.50 per line."
The $6.50 per-line charge to residential customers for Caller ID covers C&P's cost to provide the service, he said.
Mr. Glynn said that in addition to the cost, he is concerned that some centrex customers might use Caller ID to engage in "redlining," discriminating against callers on a socioeconomic basis.
By cross-referencing telephone numbers with street addresses and other demographic data, a feat that can be accomplished by using special computer software, some businesses might attempt to use Caller ID to reveal more than just the phone numbers of callers, Mr. Glynn said.
Mr. Glynn said that he feared some callers whose telephone exchanges indicate they live in a poorer section of town might run the risk of being treated differently than those calling from affluent neighborhoods. He said that Caller ID makes that type of discrimination easy to engage in and difficult to detect.
"Businesses may try to draw conclusions about whether somebody falls into a class of people they want to target for marketing purposes," Mr. Glynn said.
"It may be an incorrect conclusion, but they may draw it anyway if they know where you're calling from," he said.
George N. Buntin, executive director of the local office of the National Association for the Advancement of Colored People, said that the practice of using Caller ID-type services to engage in redlining has long been a concern at the NAACP.
C&P's Mr. Burman dismissed such concerns as unfounded.
"I'm not sure in this economic climate that any business would say no to any potential business client," he said.