Appendix C Using the ROM Monitor

Entering the ROM Monitor Mode

•reset or i—Reset and initialize the router, similar to power-on.

•tftpdnld—Download an image using Trivial File Transfer Protocol (TFTP) from a remote server.

•show rom-monitor—Shows version of read-only ROMMON, and if present, the upgrade version of ROMMON. It also shows the current version of ROMMON, which version will be selected for execution when the Cisco IOS software is booted again. This command is available in the Cisco IOS EXEC mode.

–showmon—Available in the ROMMON command mode. Provides the same information as the show rom-monitorcommand in the Cisco IOS EXEC mode.

•upgrade rom-monitor[file<URL>preference[readonlyupgrade]]—Installs and reloads a new version of ROMMON in the Cisco IOS exec mode. URL refers to the path where the new ROMMON image is stored. Prompts the user to save the configuration.

–upgrade rom-monitor preference [readonlyupgrade]—Selects the version of ROMMON to be loaded the next time the router is reloaded. This command is used in the Cisco IOS EXEC mode.

–rommon-pref—Used in ROMMON command mode. Provides the same information as upgrade rom-monitor preference command in the Cisco IOS EXEC mode.

–fpga-pref[readonlysystem]—Field Programmable Gate-Array (FPGA), used in ROMMON command mode. Selects which FPGA to run.

Debugging Commands

Most debugging commands are functional only when Cisco IOS software has crashed or is aborted. If you enter a debugging command and Cisco IOS crash information is not available, the following error message appears:

“xxx: kernel context state is invalid, can not proceed.”

•stack or k—Produces a stack trace.

•context—Displays processor context.

•frame—Displays an individual stack frame.

•sysret—Displays return information from the last booted system image. This information includes the reason for terminating the image, a stack dump of up to eight frames, and, if an exception is involved, the address where the exception occurred. For example:

rommon 8 > sysret

System Return Info:

count: 19, reason: a SegV exception

pc:0x802b1040, error address: 0x802b1040 Stack Trace:

FP: 0x80908398, PC: 0x802b102c

FP: 0x809083b0, PC: 0x802b0b88

FP: 0x809083d8, PC: 0x8017039c

FP: 0x809083e8, PC: 0x8016f764

Configuration Register Commands

The virtual configuration register resides in NVRAM. You can display or modify the virtual configuration register from either the ROM monitor or the operating system software.

Cisco VG224 Voice Gateway Software Configuration Guide

 

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Cisco Systems VG224 manual Debugging Commands, Configuration Register Commands
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VG224 specifications

The Cisco Systems VG224 is a versatile VoIP (Voice over Internet Protocol) gateway designed to facilitate the integration of traditional phone systems with modern IP-based communications. This device plays a crucial role in providing connectivity between analog phones and digital networks, allowing organizations to transition smoothly from legacy telephony systems to IP telephony.

One of the standout features of the VG224 is its ability to support up to 24 analog phone lines. This scalability makes it an ideal choice for small to medium-sized businesses that require a dependable solution to handle their telephony needs without overspending on infrastructure. The VG224 acts as a bridge, converting analog voice signals into digital IP packets, thus enabling seamless communication over the Internet or intranets.

The VG224 is equipped with a range of technologies that enhance its functionality and reliability. Voice activity detection (VAD), comfort noise generation (CNG), and echo cancellation are just some examples of the advanced audio processing techniques integrated into the VG224. These technologies improve call quality by ensuring clear and uninterrupted conversations, even under varying network conditions.

In terms of characteristics, the VG224 features a user-friendly interface with a web-based management console, making it easy for network administrators to configure and manage the device remotely. This streamlined approach to management is crucial for businesses that require quick adjustments to their communication infrastructure without the need for extensive technical knowledge.

The VG224 supports multiple signaling protocols, including H.323, MGCP (Media Gateway Control Protocol), and SIP (Session Initiation Protocol). This flexibility allows it to integrate seamlessly with various IP telephony systems and offers businesses the option to utilize their preferred communication standards. Additionally, the device supports power over Ethernet (PoE), providing the convenience of powering devices through the same cable used for data connectivity, thus reducing the need for additional power sources.

In conclusion, the Cisco Systems VG224 is a robust VoIP gateway that combines advanced technology with user-friendly features. Its capacity to support up to 24 analog lines, along with its compatibility with various signaling protocols, makes it an excellent choice for businesses looking to modernize their telecommunication systems while maintaining the reliability of traditional analog connections. With its ease of management and high-quality voice processing capabilities, the VG224 stands out as a key asset for any organization aiming to optimize its communication infrastructure.
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