Break key sequence simulation is useful if your terminal emulator does not support the break key, or if a bug does not allow your terminal emulator to send the correct signal.
Complete these steps to simulate a break key sequence:
- Connect to the router with these terminal settings:
- 1200 baud rate
- No parity
- 8 data bits
- 1 stop bit
- No flow control
- You no longer see any output on your screen, and this is normal.
- Power cycle (switch off and then on) the router and press the SPACEBAR for 10-15 seconds in order to generate a signal similar to the break sequence.
- Disconnect your terminal, and reconnect with a 9600 baud rate. You enter the ROM Monitor mode.
Remember: The Electronic Industries Association leavingcisco.com RS-232 logic level uses +3 to +25 volts to signify a Space (Logic 0) and -3 to -25 volts for a Mark (logic 1). A break signal is when the data line remains in the space condition for a specified duration, usually 100 ms to ½ second. All characters begin with a start bit and end with a stop bit (and also a parity bit or two). The level condition of the start and stop bits is always opposite. So, no character combination can look like the break signal.
Remember: In some cases, the break sequence might not get transmitted properly when using a USB/Serial converter cable. In such cases, use a keyboard with a different connector port (for example, a PS/2).