A Cisco 2600 or 3600 series router boots to ROMmon mode when a modem is attached to the console port


Wed, 11/18/2009 - 18:25
Jun 22nd, 2009
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Core Issue

This occurs when the router is reloaded, and is caused by echoing being enabled on the modem.


If a Cisco 2600 or 3600 series router goes into ROM Monitor (ROMmon) mode after a reload when a modem is connected to the console port, perform the following steps:

  1. If possible, disconnect the modem from the console port and reload the router to be sure the modem is causing the router to go into ROMmon mode.
  2. If the router boots normally without the modem connected, disable echoing on the modem. Contact the modem manufacturer for procedures on disabling echo.
  3. After the echo feature is disabled, reconnect the modem to the router's console port, and reload the router in order to test the workaround.


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