The Cisco NM-4A Network Module provides 4-port and 8-port asynchronous and synchronous serial interfaces for Cisco devices, expanding the availability of serial connectivity on a single module. It supports both asynchronous and synchronous traffic across multiple ports, enabling flexible WAN or lab networking configurations on compatible hardware. Designed for installation in supported Cisco routers or switches, the NM-4A adds scalable port capacity for serial networks.
