By Alina Selyukh WASHINGTON (Reuters) – U.S. communications regulators on Wednesday reminded Internet service providers to promise consumers only the speed and quality of service that they actually deliver, or face penalties. In an advisory, the Federal Communications Commission urged both fixed and wireless Internet service providers (ISPs) to comply with regulations that say the companies must be clear and accurate in the information they tell consumers about their broadband services. The warning shot to ISPs, such as Comcast Corp and Verizon Communications Inc, comes as the agency crafts new net neutrality rules that guide how broadband providers manage web traffic on their networks. The transparency regulations are the only part of the previous net neutrality rules set in 2011 that were struck down in court in January.