美国ISD公司生产的语音录放电路系列品种齐全，不仅有单片6－20秒的、32-120秒和60～240秒的，还有］F申片时间长达山。时（外接存储能）的语音电路。ISD4O00系列中的4002、4003和4004单片录放时间分别为2～4分钟、4～8分钟和8～16分钟，这是现阶段音质最好的单片录放时间最长 American ISD voice recording circuit series produced by the full range of products, not only a single 6-20 seconds, 32-120 seconds and 60 to 240 seconds, there are] F as long as the mountains for the application. When (external storage) voice circuit. The 4002, 4003 and 4004 monolithic recording and playback times in the ISD4O00 series are respectively 2 to 4 minutes, 4 to 8 minutes and 8 to 16 minutes, which is the longest monolithic recording time at the present stage