Cisco NM-16A 3600 16 Port Asynchronous Module The 16-port (NM-16A) asynchronous (async) network modules provide 16 EIA/TIA-232 (formerly know as RS-232) data terminal equipment (DTE) serial interfaces at speeds up to 134.4 kbps. These modules use the 68-pin OCTAL Cables such as the CAB-OCTAL-ASYNC= and CAB-OCTAL-MODEM=. The NM-16A module is often used to provide out of band connectivity to the console ports of other devices in a comm/terminal server setup.