Importance

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Abstract

A personal computer attachment is provided for a display station of the type that communicates with a host computer (48). The display station has a display unit (10) and a keyboard (12) to which a personal computer system unit (14) is attached. The personal computer system unit typically supports floppy diskette drives (16) and a printer (18). The display unit includes a CRT (38), a regeneration buffer (42), a keyboard adapter (46) and a feature bus (44). The personal computer system unit includes a system bus, a microprocessor, memory, a keyboard adapter and I/O interface connected to the system bus. A display adapter (26 or 28) is connected to the I/O interface. An analog input switch (52) is disposed between the buffer (42) and the analog circuits driving the CRT (38). This switch has a second input from the display adapter (26 or 28) and is controlled from inputs from the keyboard (12) to selectively supply image data from the buffer (42 ) or the display adapter (26 or 28). An attachment adapter (36) mates with the I/O interface of the personal computer system unit. The adapter (36) includes an input/output interface (54), a switch control (56), a two-way keyboard adapter (58) and a feature bus adapter (60). The keyboard (12) is connected to the two-way keyboard adapter (58). Each of the switch control (56), the two-way keyboard adapter (58) and the feature bus adapter (60) communicate with the system bus of the personal computer system unit via the input/output interface. The switch control (56) is also connected to the control input of the analog input switch (52). The two-way keyboard adapter (58) is also connected to the keyboard adapter in the display station and the keyboard adapter in the personal computer system unit. The feature bus adapter (60) is also connected to the feature bus (44) of the display station. This arrangement allows keystroke signals from the keyboard (12) to be transmitted by the two-way keyboard adapter (58) via the input/output interface (54) and system bus to the memory in the personal computer system unit for interpretation by the microprocessor and then retransmitted back to the two-way keyboard adapter and then to a designated one of the keyboard adapters in either the display station or the personal computer system unit. The switch control is responsive to a unique keystroke signal to control the analog input switch (52). In this way, the operator can control the mode of operation between either a host mode or a personal computer mode. Further, data transfer can be made between the host computer and the personal computer.

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First Claim