Compare Cisco (PA-8T-X21=) Expansion Module to Cisco NM-HDA-4FXS (NM-HDA-4FXS=) Expansion Module

The PA-8T-X21 provides up to eight synchronous serial interfaces for the Cisco 7000 family routers and the Cisco uBR7200 series routers. PA-8T-X21 network interfaces provide a direct connection between the high-speed bus in the router and external networks. Each PA-8T-X21 interface provides full-duplex (FDX) operation at T1 (1.544 Mbps) and E1 (2.048 Mbps) speeds. The X.21 interface is commonly used in the United Kingdom to connect to public data networks.??All eight PA-8T-X21 interfaces connect to external networks through a single port that has a 200-pin, D-shell receptacle. You must use an X.21 compact serial cable to connect PA-8T-X21 interfaces to an external data service unit (DSU) or channel service unit (CSU). The compact serial cable attached to the single receptacle determines the mode (DCE or DTE) for all eight interfaces. Less

he voice/fax modules enable packet voice technologies including voice over IP(VoIP), voice over Frame Relay (VoFR) and voice over ATM (VoATM). Cisco voice solutions provide the means for integrating both voice and data within a single network allowing users to take advantage of services, such as toll-bypass, without sacrificing voice quality.The Cisco High-Density Analog Voice and Fax Network Module provides DTMF detection, voice compression and decompression, call progress tone generation, voice activity detection (VAD), echo cancellation, and adaptive jitter buffering. Less