Patent ID: 8428424

Claim:
A digital video recorder (DVR), being connected with a controller and a multiplexer, the DVR comprising: a processor; a command output interface; a signal output interface; a storage unit to store different voice data formats; and a channel test unit stored in the storage unit and being executable by the processor, the channel test unit comprising: a command generation module to generate a selection signal and send the selection signal to the controller through the command output interface, the controller to output control signals to address input terminals of the multiplexer according to the selection signal, to select an output terminal of the multiplexer to switch to a signal channel to be tested from the signal channels; a signal generation module to obtain a format voice data from the storage unit and convert the voice data to an analog voice signal, and send the analog voice signal to the input terminal of the multiplexer through the signal output interface, the multiplexer to send the analog voice signal to the selected signal channel after the signal channel is selected; a voice detection module to define an identification (ID) number for each of the signal channels of the DVR in sequence, and detect whether the DVR receives an analog voice signal from the selected signal channel, and determine whether all of the signal channels have been tested according to the ID numbers; and a display module to display an ID number of the selected signal channel on a display device when the DVR does not receive the analog voice signal from the selected signal channel.