NM-16A Configuration for Terminal Server in ISR

When I started with my CCIE Journey, I had some 2511 to make sure I had remote console access. For my current lab I had to configure a NM-16A in an ISR router. How to set it up? Of course there is good documentation to Configure a Terminal but not everything was in that post.


The NM-16A is an async module for an ISR with 16 connections. First of all, let’s check if there is a NM-16A module in the router with the following command:

show hw-module all attribute

show hw-module all attribute
Slot 0 Bay 1 Board 0 Module[NIM-16A] spa_type 0xD1F Daughter Board Not Present
Base mac_addr 084f.f9a7.080c mac_blk_sz 4 Endpt MAC Address offset(s) : 0
Basic attributes : length 12, version [3], module-type [ngio], width [Single Wide]
Power Rating [20], Control Endpoint count [1], Daughter Board Count [0]
KR Support [0x00], 16-bit GPIO [Not present], Submodule reset support [Not required]

Extended Attributes for [16 ports Async Serial NIM]
GPIO Pin Information
Input Pin[Daughter board presence]
Output Pin[Boot select]
Input Pin[PRI interface ready]

I2C Information
[dev_addr 0xA dev_type clock]

Port type async serial Range [0 15] Per-port Information : Max IID [1] Connector [rs232] Network clocking [disable]
Module OID: 1 3 6 1 4 1 9 12 3 1 9 105 31
Port OID: 1 3 6 1 4 1 9 12 3 1 10 8

This was just a snippet.

NM-16A Configuration

The following configuration is working for me. I like to have a password on the lines.

Running Config of Line 0/1/0 0/1/15

line 0/1/0 0/1/15
session-timeout 20
exec-timeout 0 0
password Cisco123!
logging synchronous
no exec
transport input all
transport output none

To configure a name to connect to a console port, you must know the line numbers. Here you see all the lines of the ISR:

show line on isr router
show line

To connect to line 0/1/0 you see the number 2 as line number. You can connect to the loopback address of the router on port 2000 + line number. In this case it will be 2002.

Commands in Running-Config

ip host asa 2002
no ip domain lookup

The ip address is the loopback 0 interface of the router.

Connect to another router via the async line.

To open a console connection to the ASA, I easily can type ASA and it will connect to loopback address on port 2002.

Login into a line (Console to ASA)
Login with an async connection to the console port of the ASA

During the session on the ASA, when you hit CTRL+SHIFT+6 / X you will return to the router and the session is still open.

Switch between sessions.
resume <number> will switch between sessions.

Whit show sessions you see the sessions that are open and you can switch between them.

show sessions
show sessions

To reset the line, you can disconnect the correct line number.

ISR4300_Console#disconnect 1
Closing connection to asa [confirm]

To verify all connections are closed:

ISR4300_Console#sh sessions
% No connections open

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