The 16-port (NM-16A) and 32-port (NM-32A) asynchronous (async) network
modules provide 16 or 32 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 and NM-32A modules are often used to provide out of band connectivity to
the console ports of other devices in a comm/terminal server setup.
The information in this document was created from the devices in a
specific lab environment. All of the devices used in this document started with
a cleared (default) configuration. If your network is live, make sure that you
understand the potential impact of any command.
Note: The Cisco IOS® software releases provided are typically the minimum
version required to support the platform, module, or feature in question. Use
(registered customers only)
to choose appropriate software for
your network device: match software features to Cisco IOS and CatOS releases,
compare IOS releases, or find out which software releases support your
The NM-16A and NM-32A modules are often used to provide out of band
connectivity to the console ports of other devices. In order to configure the
router as a comm server, refer to these documents:
On the 16- and 32-port async network modules, the interfaces are
addressed as interface async <line number>.
Previous releases of Cisco IOS software reserved 16 async line numbers
per network module slot. This causes problems for a 32-port async network
module. Thus, when the NM-16A or NM-32A module is installed in the Cisco 3600,
Cisco IOS software will reserve 32 line numbers per slot. This will cause a
problem if the NM-16A or NM-32A module is installed into a system that already
had an async configuration based on 16 line numbers per slot. The aux port will
now be line 65 on the Cisco 2600 and Cisco 3620, and line 129 on the Cisco
3640. You can use the show line command to check the
line numbering on the chassis.