You could transmit the a character code to the video display to generate an echo right after subtracting the a character code from a carriage return . 从“回车”字符减去A字符代码后，你便可以将A字符代码传送到荧光屏显示器，以便立即产生一个回波检验信号。
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You could transmit the a character code to the video display to generate an echo right after subtracting the a character code from a carriage return 从“回车”字符减去a字符代码后，你便可以将a字符代码传送到荧光屏显示器，以便立即产生一个回波检验信号。
