Analog Phone Connectivity
Cisco 450 Voice Gateway are ideal for analog phone deployments ranging from centralized to sparsely
concentrated or distributed topologies. Cisco 4000 Series Integrated Services Routers offer many supplementary
analog calling features, depending on the call control and signaling type used. All supplementary analog
features are supported through the FXS and FXO service modules. The analog interface on Cisco 4000 Series
also supports Feature Access Codes (FACs) for invoking supplementary services.
Fax and Modem Connectivity
FXS ports on Cisco 450 Voice Gateway support fax machines and modems. When using fax machines, the
gateways support T.38 fax relay and fax pass-through. T.38 fax relay technologies allow transfer of faxes
across the network with high reliability using less bandwidth than a voice call. All modems can be connected
to the Cisco VG Series Gateways and are transferred over the network using modem pass-through.
Protocols Supported
The voice gateways support the following protocols:
• SCCP
• H.323v4
• MGCP
• SIP
• Real-Time Transport Protocol (RTP)
• Secure Real-Time Transport Protocol (SRTP)
• Trivial File Transfer Protocol (TFTP)
• HTTP server
• Simple Network Management Protocol (SNMP)
• Telnet
• Dynamic Host Configuration Protocol (DHCP)
• DNS
• Cisco Unified Communications Manager or Cisco Unified Communications Manager Express redundancy
support using Hot Standby Router Protocol (HSRP)
• Call survivability: MGCP failover to an H.323 connection to the Survivable Remote Site Telephony
(SRST) router
• T.38 fax relay and modem pass-through
• Codec support: G.711, G.729. G.729a will be used if the gateway does not support G729 annex b
• RADIUS and for Telnet and authorization
The following table lists the feature specifications for Cisco 450 Voice Gateway.
Table 1: Cisco SM-X Single-Wide Service Module Feature Specifications
SM-X-72FXS
SM-X-24FXS/4FXO
SM-X-16FXS/2FXO
SM-X-8FXS/12FXO
Feature
Tip and Ring
Interface for each
FXS port
Cisco 450 Voice Gateway Hardware Installation Guide
3
Overview of Cisco VG450 Voice Gateway
Analog Phone Connectivity
