程控交换机有时发生“死机”故障，有时却没有发生，有时发生的次数比较多，有时发生的次数却少，因此，程控交换机的死机故障分为暂时性故障、随机性故障。引起程控交换机“死机”故障的原因主要有以下几个：清零复位信号出现问题、时钟脉冲信号出现问题、噪音干抗引起的问题、时延以及环境条件问题。本文主要对HJD-04 程控交换机的“死机”故障进行分析，探析引起死机的以上几个原因。-PBX occasional " crash"　failure, sometimes does not occur, the number of occurrences sometimes more, sometimes less, but the frequency of occurrence, therefore, divided into program-controlled switches, a temporary failure of crash failures, random failures. Caused by program-controlled switches, " crash"　the causes are the following: Clear Reset signal problems, problems with the clock pulse signal, the noise problems caused by anti-dried, and environmental conditions of delay. This paper, the HJD-04 program-controlled switches, " death"　failure analysis, Analysis of crashes caused more than a few reasons.