Chapter 2 Planning Your Installation

Distance Limitations for Interface Cables

•FXS Analog Voice Port Maximum Distance, page 2-3

•Interference Considerations, page 2-3

Fast Ethernet Maximum Distance

The maximum segment distance for Fast Ethernet is 330 feet (100 meters) (specified in IEEE 802.3).

FXS Analog Voice Port Maximum Distance

The maximum distance is established by a total allowable loop resistance, including the phone or terminal equipment, of 600 Ohm.

Interference Considerations

When you run cables for any significant distance in an electromagnetic field, interference can occur between the electromagnetic field and the signals on the cables. This has two implications for the installation of terminal plant cabling:

•Unshielded plant cabling can emit radio interference.

•Strong electromagnetic interference (EMI), especially caused by lightning or radio transmitters, can destroy the EIA/TIA-232 drivers and receivers in the Cisco VG202, Cisco VG202XM,

Cisco VG204, or Cisco VG204XM voice gateways.

If you use twisted-pair cables with a good distribution of grounding conductors in your plant cabling, emitted radio interference is unlikely.

If your cables exceed the recommended distances, or if your cables pass between buildings, you must give special consideration to the effect of lightning strikes or ground loops. If your site has these characteristics, consult experts in lightning suppression and shielding. The electromagnetic pulse caused by lightning or other high-energy phenomena can easily couple enough energy into unshielded conductors to destroy electronic devices.

Most data centers cannot resolve the infrequent but potentially catastrophic problems of EMI without using pulse meters and other special equipment. Take precautions to avoid these problems by providing a properly grounded and shielded environment and by installing electrical surge suppression.

If you remove any module, you must either install a module in its place or install a cover plate over the opening. To prevent electromagnetic interference, all module openings must be either occupied or covered.

For advice on the prevention of electromagnetic interference, consult experts in radio-frequency interference (RFI).

Cisco VG202, Cisco VG202XM, Cisco VG204, and Cisco VG204XM Voice Gateways Hardware Installation Guide

 

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Cisco Systems VG204 Fast Ethernet Maximum Distance, FXS Analog Voice Port Maximum Distance, Interference Considerations
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VG202, VG204XM, VG204, VG202XM specifications

Cisco Systems has long been a leader in the realm of networking technology, providing innovative solutions for businesses of all sizes. Among its products, the Cisco VG202XM, VG204, VG204XM, and VG202 series stand out as vital components in voice gateway solutions for IP telephony applications.

The Cisco VG202XM and VG204 series are designed to facilitate the convergence of voice and data as businesses transition to VoIP (Voice over Internet Protocol). These voice gateways offer seamless integration with legacy telephony systems while enabling the deployment of advanced IP-based telephony features. They are particularly useful for organizations looking to preserve their existing investments in traditional telephony infrastructure while embracing modern communication technologies.

One of the main features of the VG202XM and VG204 series is their support for two-line interfaces, catering to varying deployment needs. The VG202 provides two FXS (Foreign Exchange Station) ports, which allow businesses to connect analog phones and fax machines directly. The VG204 enhances this capability by offering four FXS ports, accommodating larger user bases and providing more connections for local telephony equipment.

These gateways support an array of voice codecs and can handle up to 16 concurrent calls, ensuring high-quality voice communication in busy environments. Their integration with Cisco's Unified Communications Manager allows users to access a host of advanced telephony features such as call forwarding, voicemail, and conferencing.

On the technology front, the VG202XM and VG204 series support both SIP (Session Initiation Protocol) and H.323 protocols, making them versatile for varied network environments. They also offer advanced QoS (Quality of Service) capabilities, ensuring that voice traffic is prioritized over other types of data, which is essential in maintaining call clarity and reliability.

Additionally, the VG204XM variant adds built-in safety features, such as power over Ethernet (PoE), which eliminates the need for separate power supplies for connected devices. This not only streamlines deployment but also enhances the reliability of the voice system.

In terms of management, these devices are equipped with Cisco's user-friendly interface, which simplifies configuration and monitoring. They can be managed through various tools offered by Cisco, making it easier for IT departments to maintain and optimize their voice services.

Overall, the Cisco VG202XM, VG204, VG204XM, and VG202 series deliver robust, scalable, and reliable solutions for businesses aiming to leverage the benefits of voice gateways in their enterprise networks. These devices not only provide essential voice capabilities but also pave the way for future growth and integration in an increasingly digital world.
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