This document explains the correct settings to apply when you connect a
PC to a router's console port. This document also details how to use the PC's
Hyper Terminal to configure and monitor a router.
There are no specific requirements for this document.
This document is not restricted to specific software and hardware
The information presented in this document was created from 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, ensure that
you understand the potential impact of any command before you use it.
For more information on document conventions, refer to the
Technical Tips Conventions.
When a console cable is connected from a PC's COM serial port to the
router, a router prompt does not appear on the Hyper Terminal. Garbage
characters appear on the Hyper Terminal, and the router no longer accepts
keystrokes. It appears as if the router is hanging and is not
The settings in the Hyper Terminal need to be set correctly; otherwise,
"strange-looking" or garbage characters may show up on the screen. When you set
up the connection, use these settings:
Bits per sec : 9600
Data bits : 8
Parity : none
Stop bits : 1
Flow control : none
Here is a screenshot of how to configure these settings on a
Windows-based PC running Hyper Terminal:
Without these settings, the router may display but does not accept any
keystrokes. The router, therefore, appears as if it is hung or has crashed.
With the correct settings, you can use Hyper Terminal to configure and monitor
Note: On some routers the console speed has been changed in the
configuration register, and a bits-per-second speed of 9600 does not work.
However, this situation is not common. Valid speeds (other than 9600bps)
include 1200, 2400, and 4800 bps. On some platforms, notably the 3600 Series
Routers, 19200, 38400, 57600 and 115200 bps are supported. Try these if you
fail to connect with the settings described in this document.
This issue can be due to any of these reasons: