For seven straight nights recently, Diana Steele of Rockville had the thrill of speaking to her husband, Lt. Cmdr. Jeffrey S. Steele, a U.S. Navy medical officer serving in the Persian Gulf.

Forewarned that overseas phone rates were steep, the Steeles tried to economize. They limited their calls to just a few minutes each and the conversations seemed to be over before they began.

Then Diana Steele got her phone bill: $250. "I was shocked," she said yesterday.

Around the country, many families with loved ones in the Persian Gulf feel the same way. Although telephone calls to the war zone are a treasured link and source of comfort, many families are ignorant of the cost and in some cases cannot pay the bills.

"Clearly there has been some disinformation and confusion" over billing rates, said AT&T spokesman Herb Linnen. Despite efforts to inform GIs of the costs, Linnen said, rumors abound in the war zone that all calls are billed as if they originated in New York or are free, as AT&T's were briefly last fall.

One family ran up a $1,400 bill, Linnen said. And the local phone company of a Texas woman last month disconnected her newly installed phone after she declined to pay immediately a $424 bill run up talking to her husband in the gulf.

According to Marta Greytok, a member of the Public Utility Commission of Texas, who has taken up the issue, bills of $500 to $800 are common in military families.

AT&T last week set up a special hot line, 1-800-323-HELP, which service families can call to hash out gulf bills, and is getting more than 1,000 calls a day on it. It is intended only for people with family in the gulf.

Officials at the Federal Communications Commission have begun studying how it might lower the rates. "We want to make sure our servicemen and women are charged fair prices that reflect only legitimate, underlying costs," FCC Chairman Alfred Sikes said in a statement yesterday.

The phone service in the gulf marks another wartime first: allowing soldiers to call home simply, if not inexpensively, from a combat zone. Pilots can return from raids over Iraq and call home almost immediately. Long-distance companies have set up large phone centers in the desert, with satellite dishes beaming their calls directly home.

AT&T has installed 1,000 special phones in Saudi Arabia. GIs who pick them up are immediately connected to an operator in the United States. If they call collect, a 10-minute conversation costs $19; if they use a credit card, it runs about $16.

MCI Communications Corp. is also present, with 120 phones, as is a company called Military Communications Corp., which in normal times handles telephones on military bases in the United States. US Sprint Communications Co. has a service that provides free phone calls through amateur radio operators.

Reports that Saudi Arabia is collecting fees on calls -- 73 cents per minute in the case of the AT&T special phones -- even when they make no use of the Saudi phone system, has engendered criticism. "We're over there defending them," said Greytok, suggesting the Saudis should waive the charge.

Confusion over billing has been heightened by the fact that some calls were free. AT&T offered free calls for three one-week periods before war broke out, but otherwise it has charged for them. Linnen said that rates are posted at its telephones in Saudi Arabia but that not everyone seems to have got the message.

Linnen said the free calling cost AT&T about $7 million; it has spent about $1.3 million more on a free service that lets people send facsimile messages to the gulf from military bases and AT&T retail stores. Rates it charges for gulf toll calls to the United States are set essentially at a break-even basis, he said, while AT&T loses money on every call from Saudi Arabia to U.S. bases in Germany, from which many servicemen were shipped to the gulf. Currently, about 25,000 calls are being placed daily on the AT&T special phones, up from about 13,000 before war began on Jan. 16.

Linnen said AT&T is not offering to waive charges for families with big bills. Callers to the AT&T hot line are counseled on rates and generally referred to their local telephone companies, which act as bill collectors for AT&T and can offer installment payment plans. Linnen said some of the calls to the hot line were from people offering to donate money to offset bills run up by service families.

The FCC believes it has authority to set up special rates for gulf calls, which would be subsidized by other callers. But an official said yesterday the FCC has no plans for that now.