Cisco EM-HDA-3FXS/4FXO= Voice Network Module Networking

This 3-port FXS and 4-port FXO voice and fax expansion module provides on-premises FXS signaling to connect directly to a standard telephone, fax machine, or similar device and supplies ring, voltage, and dial tone. In addition, the FXO ports provide off-premises connection to the central office. FXS signaling support available includes loop-start and ground-start. There is no DID support. In addition, there is no FXO power failover support on the FXO ports. It also supports analog Centralized Automated Message Accounting (CAMA) on any port.