The Telephone Consumer Protection Act was signed into law in 1991 as a response to a growing rise in unregulated and harassing telemarketing calls and faxes. The TCPA regulation limits the use of pre-recorded voice messages, automatic dialing, SMS, and fax. Without explicit customer consent, companies must adhere to strict solicitation rules, solicitors must honor the National Do Not Call Registry, and subscribers may sue a company that does not follow TCPA guidelines. Any violations may result in a fine of up to $500 per violation from the Federal Communications Commission. In some cases, the fines from the FCC may be in the tens of millions for violation of telephone solicitation laws.