WASHINGTON – A decade after families of prison inmates asked for action, the Federal Communications Commission agreed on Friday to limit how much companies can charge for phone calls made from behind bars.

The FCC voted 2-1 during an emotional meeting to cap interstate phone rates at 21 cents a minute for debit or prepaid calls and 25 cents a minute for collect calls. Companies wanting to set higher rates would have to file a request for a waiver and could not charge more until that waiver is granted.

“For 10 years, the families and friends of inmates have been asking the FCC to ease the burden of an inmate calling rate structure. Their wait is finally over,” said FCC acting chairwoman Mignon Clyburn, who took over the interim spot in May.

The commission’s action ends fluctuating phone rates for inmates that vary depending on the provider, the type of call and size of prison facility. The fees range from 50 cents to $3.95 to place calls, plus additional per-minute rates of anywhere from 5 cents to 89 cents. In some cases, a 15-minute call has cost $17, and numerous fees have been tacked onto call charges. Inmates’ families, many of them poor, usually are stuck with the bills. For security, inmates are not allowed to have cellphones.

Clyburn’s voice, and that of Commissioner Jessica Rosenworcel, cracked with emotion as they read statements about the decision. The audience, which included family members of inmates, broke out in applause after the vote.

Stephanie Joyce, an attorney who represents Dallas-based Securus Technologies Inc., one of the two largest providers of inmate phone services, said the company was withholding comment until the release of the actual order from the commission. Mark Kollar, an attorney representing American Securities, which owns the other large provider, Global Tel-Link, declined to comment.