Abstract: A data adapter for simultaneously providing a low speed channel, a first high speed data channel, and a second high speed channel over a two wire connection; the two wire connection connects the data adapter to a telephone system. The data adapter includes a line transceiver connected to the two-wire connection, the line interface provides a full duplex transmission link with the telephone system over the two-wire connection. A telephone interface converts data between the first high speed channel and a telephone instrument. A rate adapter converts data between the second high speed channel and a data processing equipment. A protocol controller performs a packet protocol on the low speed channel, and routes the first high speed channel to the telephone interface and the second high speed channel to the rate adapter.

Abstract: This circuit provides a minimally sized data transfer buffer interface between two central processing units for transferring data blocks of variable size. The circuit provides an indication to one CPU that the other CPU has received all the data words transmitted.