DESC: ADTRAN, Inc. designs, develops, and manufactures ADvanced TRANsmission products for high-speed digital communications. ADTRAN commitment to total customer satisfaction requires continually developing and improving products to meet changing needs while maintaining the highest level of quality. That's why a complete collection of modular and scalable ADTRAN solutions is provided with a broad range of options for management, network, and local loop interfaces.??The ADTRAN Total Access Ear and Mouth /Transmit Only Dataport (E&M/TO) is an access module, usually used for Private Branch Exchange (PBX) and voice applications, that plugs into a single channel slot of a Total Access 1500 platform. The unit is multifunctional and can be provisioned to operate in two-wire E&M, four-wire E&M, two-wire TO, and four-wire TO.