Front Panel, 1000BASE-T Port | 3Com 10BASE-T specification

HOW TO USE THE BASELINE 10/100 SWITCH 24-PORT

The numbers in this diagram refer to numbered sections in the text.

Front Panel

124 RJ-45 10/100 Ports and 1 RJ-45 1000 Port

WARNING: RJ-45 ports. These are shielded RJ-45 data sockets. They cannot be used as telephone sockets. Only connect RJ-45 data connectors to these sockets. Either shielded or unshielded data cables with shielded or unshielded jacks can be connected to these data sockets. AVERTISSEMENT: Les ports RJ-45. Il s’agit de prises femelles blindées de données RJ-45. Vous ne pouvez pas les utiliser comme prise de téléphone. Branchez unique- ment des connecteurs de données RJ-45 sur ces prises femelles. Les câbles de données blindés ou non blindés, avec les jacks blindés ou non blindés, l’un ou l’autre, peu- vent être branchés à ces prises de courant de données. WARNUNG: RJ-45-Anschlüsse. Dies sind abgeschirmte RJ-45-Datenbuchsen. Sie können nicht als Telefon- anschlußbuchsen verwendet werden. An diesen Buchsen dürfen nur RJ-45-Datenstecker angeschlossen werden. Diese Datenstecker können entweder mit abgeschirmten oder unabgeschirmten Datenkabeln mit abgeschirmten oder unabgeschirmten Klinkensteckern verbunden wer- den.

10BASE-T/100BASE-TX Ports

The Baseline 10/100 Switch 24 Port 10BASE-T/100BASE-TX plus 1-Port 1000BASE-T has 24 10/100Mbps auto-negotiating ports. Ports 1–23 are MDIX ports. Each can be connected to a device with an MDI port (such as a workstation) using a normal ‘straight through’ TP (twisted pair) cable. Alternatively, you can connect to a device with MDIX ports using ‘cross-over’ TP cable.

Port 24 is ‘switch selectable’ MDI/MDIX using the MDI switch, as described in 2. Using this port, you can connect to any other device without the need for ‘cross-over’ cable.

Ports 1 to 24 are auto-negotiating: their speed and duplex mode (half duplex or full duplex) are automatically determined by the capabilities of the connected device. Each port can be connected to either a 10BASE-T or a 100BASE-TX device.

CAUTION: The Baseline 10/100 Switch supports full

duplex auto-negotiation. If the connected device does not ! support auto-negotiation, the Switch will operate in half duplex mode (even if the device is operating in full duplex

mode). In such a configuration, you may notice some degradation of network performance. 3Com recommends that you use devices that are capable of auto-negotiation (and that you ensure that auto-negotiation is enabled, if it is a configurable option).

1000BASE-T Port

Port 25 is a 1000BASE-T port capable of auto-negotiation with the connected port to operate at 1000BASE-T full duplex. It auto-senses an MDI/MDIX connection and can be used to connect

to either another 1000BASE-T switch port or to a 1000BASE-T server or workstation without additional configuration.

Connecting to a Network Device

To connect a device to the Baseline 10/100 Switch 24 Port 10BASE-T/100BASE-TX plus 1-Port 1000BASE-T, use Category 5 unshielded or shielded (screened) 100 Ohm TP cable (or Category 3 cable for a 10Mbps connection). The maximum length of cable for each connection is 100m (328ft). Connect one end of the cable to an RJ-45 port on the Baseline 10/100 Switch, and the other end to the appropriate RJ-45 port on the connecting device.

Connecting to another Switch or Hub

If you connect two Baseline 10/100 Switch 24 Port 10BASE-T/100BASE-TX plus 1-Port 1000BASE-T units together, 3Com recommends that you use the 1000BASE-T ports on both units for the link. You must use Category 5 cable when connecting the units.

1000BASE-T connection: To connect a Baseline 10/100 Switch

24Port 10BASE-T/100BASE-TX plus 1-Port 1000BASE-T to another Switch using the 1000BASE-T port, use a normal ‘straight through’ cable and connect each end to the 1000BASE-T port on each unit.

100BASE-TX connection: To connect the Baseline 10/100 Switch

24Port 10BASE-T/100BASE-TX plus 1-Port 1000BASE-T to a SuperStack 3 hub using a normal ‘straight through’ cable, connect any port on the Baseline 10/100 Switch 24 Port 10BASE-T/100BASE-TX plus 1-Port 1000BASE-T to the MDI/MDIX port on the hub, as shown below. Ensure that the MDI switch on the hub is in (MDI).

An alternative method of connecting the Baseline 10/100 Switch to a hub using a normal ‘straight through’ cable is to connect any MDIX port on the hub to the MDI/MDIX port on the Baseline 10/100 Switch, ensuring that its MDI Switch is set to in (MDI). You can use ‘cross-over’ TP cable to connect any MDIX port on the Baseline 10/100 Switch to any MDIX port on a hub.

10BASE-T specifications

3Com 10BASE-T is a networking technology that plays a foundational role in local area networks (LANs). Introduced in the early 1990s, it quickly became one of the most widely adopted Ethernet standards, enabling reliable data transmission over twisted-pair cabling. Designed to operate at speeds of 10 megabits per second, 10BASE-T facilitated the transition from older coaxial cable systems to more flexible cabling options, paving the way for more robust and scalable network infrastructures.

One of the defining features of 3Com 10BASE-T is its use of unshielded twisted pair (UTP) cabling, specifically Category 3 cabling at its inception. This choice of cabling allowed for easier installation and lower costs compared to coaxial cables. Furthermore, the standardized cabling allows for distances of up to 100 meters between network devices, making it suitable for various office layouts. The connectors used with 10BASE-T networks are RJ-45 connectors, which have become a staple in networking.

Another characteristic of 10BASE-T is its method of signaling. It employs Manchester encoding, which speeds up error detection and improves resilience against noise. This coding scheme allows for the transmission of 0s and 1s over a single twisted pair of wires, adding an extra layer of efficiency to the network's operation. The design also includes a built-in collision detection mechanism, which helps manage data traffic effectively, thereby maintaining network integrity.

A defining technology of 3Com's implementation of 10BASE-T is its ability to support a star topology. Unlike previous bus topology systems that relied heavily on coaxial cables, the star topology allows for individual connections to a central hub or switch. This setup not only enhances fault tolerance—since a failure in one cable does not impact other network segments—but also simplifies network management and troubleshooting.

Additionally, 3Com's 10BASE-T technology supports auto-negotiation, allowing connected devices to automatically determine the best speed and duplex setting for communication. This adaptability makes it easier to integrate newer devices into existing networks and ensures smoother transitions as technology evolves.

In summary, 3Com 10BASE-T represents a significant advancement in networking technology, characterized by its use of twisted-pair cabling, efficient Manchester encoding, star topology, and auto-negotiation capabilities. Its contributions set the stage for the development of faster and more advanced Ethernet standards, cementing its place in the history of computer networking.