From the FCC website: "The Communications Act of 1934 authorizes the Federal Communications Commission (FCC) to use civil monetary penalties as a means of enforcing Commission rules and regulations. The FCC can assess civil monetary penalties against those who violate Commission rules and regulations through either (1) an informal administrative process or (2) a formal evidentiary hearing. In the more commonly used administrative process, the Commission issues a Notice of Apparent Liability (NAL) which gives the charged party an opportunity to litigate the alleged violation and the proposed amount of the monetary penalty in a paper proceeding. Based on the pleadings submitted and the extenuating or aggravating circumstances presented, the Commission may then issue a Notice of Forfeiture (NOF), which sets the amount due. If the charged party refuses to pay the forfeiture, the Commission refers the matter to the Department of Justice for collection in district court where the charged party is entitled to a “trial de novo ” as to both liability and amount of forfeiture. The Commission may also assess a penalty after issuing a notice and conducting a full evidentiary hearing before an administrative law judge. After exhausting its administrative remedies, the charged party is entitled to seek judicial review in the United States Court of Appeals. If the violator refuses to pay the forfeiture after the Commission’s decision has become final the Commission must ask the Department of Justice (DOJ) to initiate a collection action in federal district court. However, unlike the informal NAL/NOF paper process, the collection action here is on a debt that is due and payable to the government."
The FCC does not have the power to give any jail time. After the Justice Dept. has filed a case for collection of an FCC assesment, the US District Court could order payment by a certain date and then hold the person in contempt. Jail time is given for violation of laws enacted by congress for specific actions.