Chapter 6 Troubleshooting the Cisco IP Phone

Resolving Known Issues

Step 4 From Cisco CallManager, select System > Server and verify that the server is being referred to by its IP address and not by its DNS name.

Step 5 From Cisco CallManager, select Device > Phone and verify that you have assigned the correct MAC address to this Cisco IP Phone.

Step 6 To verify the MAC address on the phone, see the “Verifying Network Settings” section on page 4-4.

Step 7 Power cycle the phone.

Resolving Known Issues

See Table 6-1for troubleshooting some common issues that might occur on your Cisco IP Phones:

Table 6-1 Cisco IP Phone Troubleshooting

Summary

Explanation

 

 

Daisy-chaining IP phones

Do not connect an IP phone to another IP phone through the

 

access port. Each IP phone should directly connect to a switch

 

port. If you connect IP phones together in a line

 

(daisy-chaining), a problem with one phone can affect all

 

subsequent phones in the line. Also, all phones on the line share

 

bandwidth.

 

 

Poor quality when calling digital cell

In Cisco CallManager, you can configure the network to use the

phones using the G.729 protocol

G.729 protocol (the default is G.711). When using G.729, calls

 

between an IP phone and a digital cellular phone will have poor

 

voice quality. Use G.729 only when absolutely necessary.

 

 

Prolonged broadcast storms cause IP

Prolonged broadcast storms (lasting several minutes) on the

phones to re-register

voice VLAN cause the IP phones to re-register with another

 

Cisco CallManager server.

 

 

 

Cisco IP Phone Administration Guide for Cisco CallManager 3.3, Cisco IP Phones 7902G/7905G/7912G

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Cisco Systems 7902G, 7905G, 7912G manual Resolving Known Issues, Summary Explanation
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7902G, 7912G, 7905G specifications

Cisco Systems is a leading provider of networking and telecommunications equipment, and among its extensive range of products, the Cisco 7900 Series of IP phones has made a notable impact in enterprise communication. Key models in this series include the Cisco 7905G, 7912G, and 7902G, each designed to enhance productivity through advanced features, intuitive interfaces, and robust technology.

The Cisco 7905G is designed for basic telephony needs and is ideal for administrative environments or areas with high call volumes. It features a large single-line LCD display, providing users with clear visibility of call information. The phone supports Power over Ethernet (PoE), making installation easier and reducing clutter by eliminating the need for an additional power supply. Its hands-free and headset support enhances user convenience, allowing for easy multitasking during calls.

Moving on to the Cisco 7912G, this model is designed for more demanding communication requirements. It features a larger, backlit display, providing improved visibility in various lighting conditions. The Cisco 7912G supports up to 12 programmable line or feature keys, giving users the flexibility to tailor the phone to their specific needs. Additionally, it incorporates advanced audio technologies, such as wideband audio for enhanced voice clarity and a built-in speakerphone, allowing users to communicate effectively in busy environments.

The Cisco 7902G, while offering basic features, is a reliable choice for users who need straightforward, cost-effective telephony solutions. It features an intuitive design with three dedicated buttons for line status, a built-in speakerphone, and support for wideband audio. The phone is geared for users who require essential telephony features without the complexity of additional functionalities, making it suitable for front-desk and general office use.

Overall, these models within the Cisco 7900 series exemplify the company's commitment to providing high-quality enterprise communication tools. With a focus on advanced audio technologies, user-friendly interfaces, and adaptability to various business environments, the Cisco 7905G, 7912G, and 7902G cater to the diverse needs of modern organizations. As companies continue to pursue seamless communication, these IP phones remain a valuable asset in their telephony infrastructure, enhancing collaboration and productivity among teams everywhere.
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