If you’re an RCN cable customer, you’ll soon see a new name on your monthly bill. The Princeton-based TV and internet provider, which serves customers in parts of the Philadelphia and Lehigh Valley regions, is rebranding itself as Astound Broadband. The new name will put RCN and its sister regional services under one national brand after several acquisitions in recent years. RCN’s parent company has already been using the Astound name. The company started updating its cable vans, uniforms, signs, and other materials with the new name earlier this month. To limit customer confusion, Astound wil…