Which three devices can be used to interface with the public switched telephone network? (Choose three.)

Cisco Unified SRST provides backup call processing for remote sites when the WAN link to CUCM fails and does not supply any physical PSTN interface.

Cisco Unified Border Element (CUBE) is a SIP session border controller that interconnects VoIP networks over IP trunks and does not provide analog or digital PSTN circuit interfaces.

A Foreign Exchange Office (FXO) voice interface card receives an analog PSTN loop-start or ground-start line from the telephone company, providing a direct physical connection point to the public telephone network.

The Cisco VG224 Analog Voice Gateway is a standalone device with 24 analog voice ports that bridges analog telephone endpoints and PSTN lines to an IP telephony infrastructure via FXO or FXS connections.

The Cisco E1/T1 ISDN PRI Network Module provides digital WAN circuit connectivity via ISDN and is not classified among the analog voice interface devices that directly interface with the PSTN in this context.

A Foreign Exchange Station (FXS) voice interface card installed in a voice gateway simulates a PSTN central-office line for analog phones and fax machines, enabling those devices to participate in PSTN calls through the gateway.