Abstract: A transmit-receive station connected to a high speed ring bus carrying data signals that may be received from and sent to each station on the ring bus has two sources of transmit clocking signals. One source is based on the frequency and phase of data signals received on the ring bus from another station and the other source is a local crystal oscillator having essentially the same frequency as the first source but in an indeterminate phase. When changing the source of clocking signals for transmission of data originating at the station, bit slippage may be minimized by providing the local oscillator output signal in four phases and using the phase most nearly aligned with the other clocking signal when the change is made. Control of access to transmit by a station employs a token having a message field of seven bits and a access control bit.

Abstract: A transmit-receive station connected to a high speed ring bus carrying data signals that may be received from and sent to each station on the ring bus has two sources of transmit clocking signals. One source is based on the frequency and phase of data signals received on the ring bus from another station and the other source is a local crystal oscillator having essentially the same frequency as the first source but in an indeterminate phase. When changing the source of clocking signals for transmission of data originating at the station, bit slippage may be minimized by providing the local oscillator output signal in four phases and using the phase most nearly aligned with the other clocking signal when the change is made. Control of access to transmit by a station employs a token having a message field of seven bits and a access control bit.

Abstract: A transmit-receive station connected to a high speed ring bus carrying data signals that may be received from and sent to each station on the ring bus has two sources of transmit clocking signals. One source is based on the frequency and phase of data signals received on the ring bus from another station and the other source is a local crystal oscillator having essentially the same frequency as the first source but in an indeterminate phase. When changing the source of clocking signals for transmission of data originating at the station, bit slippage may be minimized by providing the local oscillator output signal in four phases and using the phase most nearly aligned with the other clocking signal when the change is made.Control of access to transmit by a station employs a token having a message field of seven bits and a access control bit.