Abstract: A synchronous digital transmitter connects a data terminal equipment to a multiservice digital PABX which accesses the public switched telephone network at 64 kbit/s. It includes a system for generating a frame clock defining a 64 kbit/s data transmission channel used for the transmission of data to and from the PABX. A further system generates a bit clock at the same frequency as the data from the terminal equipment for transfers to and from the terminal equipment. A further system periodically synchronizes the bit clock to the frame clock. The transmitter is applicable to the synchronous transmission of data at data rates up to 64 kbit/s.

Abstract: An arrangement for connecting a personal computer (1) to a telephone network (2) via a digital exchange, in particular a private exchange (13), and via a telephone set (3) or subscriber terminal suitable for processing telephone signalling and enabling digital voice and data signals to be transferred simultaneously, the telephone set or subscriber terminal being controlled by an internal processor (14) of a controlling logic circuit (9) and including a data transmission (4B) for connection to a computer apparatus such as a computer. The coupler (4) is integrated in the telephone set and is connected to the controlling logic circuit (9) of the telephone set, which diverts the telephone signalling transmitted to the controlling logic circuit of the telephone towards an external access (1A1 or 1A2) to the bus of the personal computer, and which selectively replaces the telephone signalling which the telephone would normally transmit to the exchange by corresponding signalling produced by the personal computer.