据《Security》1990年12月刊报道:美国磁性元件公司和SMF公司已研制出存取控制和干扰检测系统ACS21。为了处理所有的安全管理功能(这些功能包括存取控制、干扰检测和视频监督),该独立系统配备有1BM中范围计算机。在没有外部接口的情况下,该系统能控制七八个阅读器。Magstripe和Wiegand业已 According to “Security” December 1990 issue of the report: the United States and SMF magnetic components company has developed access control and interference detection system ACS21. To handle all of the security management features that include access control, interference detection, and video surveillance, the stand-alone system is equipped with a 1BM mid-range computer. In the absence of an external interface, the system can control seven or eight readers. Magstripe and Wiegand are already