<https://facilityexecutive.com/2020/11/48900-series-plc-interlock-controller/>
<http://schema.org/description>
"The 48900 PLC Interlock Controller is a cost-effective solution for implementing door interlock and mantrap systems with up to nine doors."
<https://facilityexecutive.com/2020/11/48900-series-plc-interlock-controller/>