Cisco 4-Port Serial Shared Port Adapter - Expansion Module - 4 Ports - SPA-4XT-SERIAL-RF

• Four software-configurable serial ports
• Each port capable of 8 Mbps depending on the attached cable type
• Each port can support EIA-232, X.21, V.35, EIA-530, EIA-530A, and EIA-449 serial standards
• Capable of both DTE and DCE modes
• Support for all major encapsulations including High-Level Data Link Control (HDLC), frame relay, and Multilink Point-to-Point Protocol (MLPPP)
• Highly modular, flexible, intelligent interface processors
• Increased speed-to-service revenue
• Dramatically improved return on your routing investment

The Cisco 4-Port Serial SPA delivers flexible, high-performance WAN connectivity for enterprise and service provider networks. It provides four synchronous serial ports, each capable of speeds up to 8 Mbps.
The Cisco 4-Port Serial SPA supports a variety of interface types determined by separately purchased cable type connected to it. The supported electrical standards include EIA-232, X.21, V.35, EIA-530, EIA-530A, and EIA-449. Each port can be configured independently of the others to provide superior flexibility.
The serial interfaces can be used to aggregate WAN connections from remote sites. The ability to support 8 Mbps per port is ideal for low- and medium-density aggregation at the head end. The Cisco 4-Port Serial SPA can also be installed wherever a service provider requires an external CSU / DSU demarcation point.
The Cisco 4-Port Serial SPA can be used to transport some synchronous legacy protocols (such as X.25) over an IP network. Serial synchronous ports also help lower costs for converged networks by eliminating the need for expensive leased lines to carry low-speed traffic that is commonly associated with legacy protocols.