초록 ▼

In a cable television system in which the individual subscriber\s converter/tuner is located outside the subscriber\s premises in an external control unit (“ECU”) and controlled remotely via a subscriber processing unit (“SPU”) connected to the ECU by a drop cable, data transmitted from the SPU to t

In a cable television system in which the individual subscriber\s converter/tuner is located outside the subscriber\s premises in an external control unit (“ECU”) and controlled remotely via a subscriber processing unit (“SPU”) connected to the ECU by a drop cable, data transmitted from the SPU to the ECU (e.g., channel selection data) is verified by transmitting similar echo back data from the ECU to the SPU. The SPU compares the original and echo back data to assure that the ECU correctly received the original data.

대표청구항 ▼

A data transmission line diagnostic device comprising: a transmission line; a first electronic device for receiving manually entered input data, said first electronic device being connected to one end of said transmission line; a second electronic device connected to another end of said transmission

A data transmission line diagnostic device comprising: a transmission line; a first electronic device for receiving manually entered input data, said first electronic device being connected to one end of said transmission line; a second electronic device connected to another end of said transmission line; first data processing means located in said first electronic device for receiving said manually entered input data and for generating data corresponding to said manually entered data; first modulating means located in said first electronic device for modulating the data from said first data processing means and for transmitting modulated data to said second electronic device through said transmission line; first demodulating means located in said second electronic device for demodulating the modulated data from said first modulating means and converting the demodulated data to digital data; second data processing means for receiving the digital data from said first demodulating means and for generating echo back data having the same content as that of the digital data; second modulating means for modulating the echo back data from said second data processing means and for transmitting modulated echo back data to said first electronic device through said transmission line; second demodulating means located in said first electronic device for demodulating the modulated echo back data from said second modulating means and for reproducing the echo back data; verification means located in said first data processing means for comparing the demodulated echo back data from said second demodulating means with the manually entered input data and for visually displaying the echo back data; and means for visually displaying error display data when a noncoincidence between the demodulated echo back data and the manually entered input data is detected by said verification means, for alerting a user to defects in said transmission line and for indicating a need for transmission line maintenance.