The telephone is the only form of communication that BPO outsourcing companies use. Additional channels for customer service offered by contact centers include email, chat, internet, and applications. One or more call centers may be part of a contact center. In order to assist consumers on any channel or device, contact centers offer omnichannel support. Depending on its goods and services, the channels via which it offers customer support and the organizational structures of the company, an organization must decide whether to use a call center or a contact center.