Cisco – Invalid Characters for Passwords in Routers and Firewalls

This one has flummoxed me in the past. The commands you're looking for relate to turning on the 8-Bit character set.

Now, this may still not allow the cellular modem to send the characters via SMS (I do not have a card to test this with), however this is the only command that I know of that may help you out.

Per the Configuring Operating Characteristics for Terminals guide from Cisco (specifically the section on Specifying an International Character Display):

The classic U.S. ASCII character set is limited to 7 bits (128 characters), which adequately represents most displays in the U.S. Most defaults on the modem router work best on a 7-bit path. However, international character sets and special symbol display can require an 8-bit wide path and other handling.

You can use a 7-bit character set (such as ASCII), or you can enable a full 8-bit international character set (such as ISO 8859). This allows special graphical and international characters for use in banners and prompts, and adds special characters such as software flow control.

The commands to enable 8 bit character set are:

default-value special-character-bits 8
default-value exec-character-bits 8

To test, I tried to type æ into my lab router with the following results:

R-VOIPLAB#
R-VOIPLAB#>

Since I have the default 7-bit character lengths turned on, it interpreted the æ as angle brackets.

Now, I turned on 8 bit character sets and logged out of my session and back in (the logout is necessary to begin using the new terminal settings we just configured):

R-VOIPLAB#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
R-VOIPLAB(config)#default-value exec-character-bits 8
R-VOIPLAB(config)#default-value special-character-bits 8
R-VOIPLAB(config)#exit
R-VOIPLAB#exit

After logging back in:

R-VOIPLAB#
R-VOIPLAB#æ
R-VOIPLAB#æ, ø, å

Notes:

This testing was done with the following configuration, so your milage might vary with a different terminal emulator, different router, etc:

• Test computer: Mac OSX 10.9.2
• Terminal program: SecureCRT for Mac, Version 7.2.0
• Terminal emulation type: VT100
• Connection type: SSH
• Router: 2821
• IOS: 15.1(4)M6

From what I understand, the modem has the internal IP is 192.168.1.1 .. If that is correct, then this is pretty simple on the router ..

from the CLI, apply the following and it should work with you ...

conf t
  int FastEthernet0/0
    ip address 192.168.1.2 255.255.255.0
    speed 100
    duplex full
    exit
  ip route 0.0.0.0 0.0.0.0 192.168.1.1

Let me explain the commands ...

conf t

This allows you to access the route configuration mode.

int FastEthernet0/0

This enters the interface configuration mode, in this case the interface is FastEthernet0/0

ip address 192.168.1.2 255.255.255.0

This adds a static IP Address of 192.168.1.2 to the interface FastEthernet0/0 to be in the same subnet of the modem (192.168.1.0/24)

speed 100

This enabled the interface to use the speed 100 MB

duplex full

This enables the interface to use full duplex

ip route 0.0.0.0 0.0.0.0 192.168.1.1

This adds a default route which informs the router to send all traffic that is not found in the routing table to the modem 192.168.1.1

But this scenario won't work, because the 192.168.1.0/24 is a private range and doesn't propagate over the internet .. The best thing is to change the modem mode to bridge this allows the router to have an IP in the same subnet of the ISP which allows you to have internet access ...