A method is presented to transmit voice and fax on Digital Data Network (DDN) leased lines which guarantees high quality and real time service in a narrowband network.

• 针对窄带数字网络中传输传统语音业务的质量和实时性问题 ,提出了一种在数字数据网络 (digital data net-work,DDN)专线上传输高质量语音和传真的解决方案。