3Com 3C16722A, 3C16721A, 3C16723A manual Straight-through Cable/Crossover Cable

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Port Status LED not lit for a port that has a connection. There is a problem with this particular connection. Check that the equipment connected to the hub is powered on, operating correctly, and contains a 100BASE-TX connection. The hub can only be directly connected to equipment that can provide a 100Mbps connection (not 10Mbps only). In particular, ensure that:

You are using a 100Mbps adapter in your workstation, if connecting a workstation to the hub. If your adapter can operate at various speeds, ensure that it is set to operate at 100Mbps.

Any 10Mbps equipment that you want to link to the hub, is connected through a 10/100 hub or switch.

You are using a ‘Straight-through’ 100BASE-TX cable that is properly connected at both ends, and is not damaged. Refer to Figure 5 to compare the wiring of a straight-through and a crossover cable.

Figure 5 Straight-through Cable/Crossover Cable

Normal

Pin

Pin

 

Uplink

Normal

Pin

Pin

 

Normal

port

 

port

port

 

port

Rx+

 

1

1

 

Rx-

Rx+

 

1

1

 

Rx+

 

2

2

 

 

2

2

 

Rx-

 

 

Rx+

Rx-

 

 

Rx-

 

3

3

 

 

3

3

 

Tx+

 

 

Tx-

Tx+

 

 

Tx+

 

4

4

 

 

4

4

 

 

 

 

 

 

 

 

 

 

 

5

5

 

 

 

 

5

5

 

 

 

 

 

 

 

 

 

 

Tx-

 

6

6

 

Tx+

Tx-

 

6

6

 

Tx-

 

 

 

 

 

7

7

 

 

7

7

 

 

 

 

 

 

 

 

 

 

 

8

8

 

 

 

 

8

8

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

16

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Contents OfficeConnect Fast Ethernet Hub 4, Hub 8, Hub 3Com Corporation 5400 Bayfront Plaza Santa Clara, California Introduction Creating Your Network Page Introduction Creating Your Network Fast Ethernet Hub 4 and Hub 8-FrontFast Ethernet Hub 4 and Hub 8-Rear Power adapter socket100BASE-TX RJ-45 ports Alert LED Power LED Collision LED Fast Ethernet Hub 12-FrontUplink/Normal switch Fast Ethernet Hub 12-RearWorkstation Connections Before You StartHub Connections Rubber Feet Stacking the Units TogetherStacking Clip Positioning Your OfficeConnect Hub Securing Your HubConnecting OfficeConnect Hubs Together Connecting Workstations and Other Equipment to Your HubExample Connecting 100BASE-TX Hubs Connecting to 10BASE-T NetworksChecking Hub Connections Spot ChecksProblem Solving Straight-through Cable/Crossover Cable Networking Terminology Dimensions and Operating Conditions Dimensions and StandardsOfficeConnect Fast Ethernet Hub Standards EMCEnvironmental Statements End Of Life StatementRegulated Materials Statement Environmental Statement about the DocumentationImportant Safety Information Wichtige Sicherheitshinweise Consignes Importantes DE Sécurité Online Technical Services 3Com Knowledgebase Web ServicesTechnical Support World Wide Web SiteSupport from Your Network Supplier Support from 3ComEurope Country Telephone Number Asia, Pacific RimEurope, South Africa, and Middle East Country Telephone Number Latin America North AmericaReturning Products for Repair Country Telephone Number Fax Number3Com Corporation Limited Warranty Warranties Exclusive Disclaimer Electromagnetic Compatibility Page Page Page Part No. DUA 1672-1AAA03 Published June

3C16723A, 3C16721A, 3C16722A specifications

The 3Com 3C16722A, 3C16721A, and 3C16723A are part of a series of networking devices designed to enhance network performance, reliability, and management capabilities in various environments. These devices are primarily used in enterprise networks, catering to different sizes and types of network infrastructures.

The 3C16722A is a high-performance Ethernet switch featuring 24 ports that support 10/100/1000 Mbps speeds. Its main features include auto-MDI/MDI-X capabilities, which automatically detect connections and configure the ports accordingly, facilitating seamless integration. This switch supports VLAN (Virtual Local Area Network) functionality, enabling network segmentation and improved security. With robust forwarding capabilities, the 3C16722A ensures efficient data transfer within a network, making it ideal for organizations that require high bandwidth for data-intensive applications.

The 3C16721A, while similar to the 3C16722A, is designed for users who require fewer ports but still demand high-speed connectivity. Offering 16 ports, the 3C16721A also operates at 10/100/1000 Mbps and incorporates advanced features such as Quality of Service (QoS) settings. QoS prioritizes critical network traffic, ensuring that voice and video data are transmitted with minimal latency, which is essential for businesses that depend on real-time communication tools.

Lastly, the 3C16723A combines the functionalities of both its counterparts but extends the port offerings to cater to larger networks. Featuring 48 ports, this switch can support multiple devices simultaneously, providing extensive connectivity options. Additionally, it offers stacking support, allowing multiple switches to operate as a single unit. This capability enables network administrators to manage larger systems more efficiently and simplifies the overall network architecture.

Each of these devices utilizes advanced technologies such as Spanning Tree Protocol (STP) for loop prevention and link aggregation to enhance throughput by combining multiple connections. Security features, including port security and access control lists, are also integrated to protect sensitive data and maintain network integrity. Overall, the 3Com 3C16722A, 3C16721A, and 3C16723A are versatile networking solutions that deliver performance, scalability, and security for modern enterprise networks.