Mark's Telephone Service Inc, 74 Evans Ave, Pittsburgh, PA 15205, US

Established in 1970, American Telecom Corporation of Pennsylvania is a full-service telecommunications company, installing and maintaining communications systems. Based in Glenshaw, Pa., it is one of the leaders in local telecommunications. The company offers an array of products, which include voice over IP, business telephone systems, unified messaging and call centers. American Telecom Corporation of Pennsylvania covers services, including carrier and financial services, system design, installation, training and maintenance. It caters to the needs of small, medium and large businesses throughout the tri-state region. The company is in partnership with Iwatsu Voice Networks, ESI and Esna.