Each 16ESIU Card connects 16 digital extensions (i.e., DSX keysets). The 16ESIU has a Mode Switch (for taking the card out of service). It also has a status LED that indicates proper card operation — as well as a port activity LED that flashes faster as traffic on the card increases. You can install up to two 16ESIU Cards in a DSX-80. You can install up to six 16ESIU Cards in a DSX-160. In DSX-160, you must install a separate power supply for every two 16ESIU Cards installed.

• Digital station ports: 16 Status
• LED: Yes
• Mode switch: Yes
• Activity LED: Yes
• Max. installed in DSX-80: 2 (32 station ports)
• Max. installed in DSX-160: 6 (96 station ports)