An Integrated Voice/Data Terminal with Simple Synchronization Circuits Using an 80 kbit/s Ping-Pong Method

With recent digital technique progress, digitalization is spreading to subscriber loop systems. In-house systems will be digitalized earlier than other systems. In in-house networks, a pingpong method, especially an 80 kbit/s ping-pong method, using an existing cable pair, is superior to other digital transmission methods due to the sample system structure. For office use, a digital subscriber terminal is required to offer integrated services. However, the already reported 80 kbit/s method is insufficient to provide simultaneous and independent integrated services. This paper presents an 80 kbit/s ping-pong method which has 72 kbit/s capacity for the voice and data communications, so as to provide such integrated services. Furthermore, an experimental integrated terminal, which has simple synchronization circuits, is described.