Installation Recommendations

2MDI Switch

This switch affects port 24 only:

	Out	Port 24 is an MDIX port.
		It can be connected to a device with an MDI
MDIX		port (such as a workstation) using a normal
		‘straight through’ TP cable.
	In	Port 24 is an MDI port.
MDI		It can be connected to an MDIX port on a
MDI		device (such as a hub) using a normal
		‘straight through’ TP cable.

3Display Function Switch

his switch affects the Status LEDs described in 4 and 5:

Out This is the normal position of the switch. The Status LEDs show the Activity and Link Status of each port.

In When the switch is pressed in, the Status LEDs show the Duplex and Speed Status of each port. The switch returns to the out posi- tion when released. This switch does not affect port 25.

4Activity/Duplex Status LEDs

he first (top) and third row of LEDs, which are colored yellow, show the activity or duplex status of the related ports:

When the Display Function switch is out (its normal position), these LEDs show the activity of each port. The LED flashes

Twhen packets are received or transmitted on the port. When the Display Function switch is pressed in, these LEDs show the duplex status of each port:

On The port is operating in full duplex mode.

Off Ports 1 to 24: If the link is established, the port is operating in half duplex mode.

Port 25: No link is present.

5Link/Speed Status LEDs

he second and fourth (bottom) row of Status LEDs, which are Tcolored green, show the link or speed status of the related ports:

When the Display Function switch is out (its normal position), these LEDs show the link status of each port:

On The link has been established and the segment attached to the port is functional.

Off The link has not been established. Either nothing is connected to the port, or there is a problem:

■Check that the attached device is powered on.

■Check that the cable is the correct type and is not faulty.

If the LED is off for port 24, check the setting of the MDI switch. Refer to 2. Try toggling the MDI switch.

If the port is connected to another unit’s MDI/MDIX port, check the other unit’s MDI switch position.

If these checks do not identify the cause of a prob- lem, it may be that the unit or the device connected to the port is faulty. Contact your supplier for fur- ther advice.

TWhen the Display Function switch is pressed in, these LEDs show the speed status of each port:

On Ports 1 to 24: The port is operating at 100Mbps. Port 25: The port is operating at 1000 Mbps

Off Port 1 to 24: If the link is present, ports 1 to 24 are operating at 10Mbps.

Port 25: The link has not been established.

6Power/Self Test LED

The Power/Self test LED lights green when the unit is powered on and ready for use.

Rear Panel Connections

7Power Supply

The Baseline 10/100 Switch 24 Port 10BASE-T/100BASE-TX plus 1-Port 1000BASE-T automatically adjusts to the supply voltage. Only use the power cord that is supplied with the unit.

8Socket for Redundant Power System (RPS)

Only connect a 3Com SuperStack 3 Advanced RPS (3C16070, 3C16071, 3C16071A or 3C16071B) to this socket. An appropriate power module and cable is required. The connector on the Baseline 10/100 Switch 24 Port 10BASE-T/100BASE-TX plus 1-Port 1000BASE-T is a Type 2 socket. For details, follow the installation instructions in the guides that accompany the Advanced RPS and the power module.

9Self-adhesive Pads

The unit is supplied with four self-adhesive rubber pads.

You do not need to apply the pads if you intend to rack mount the unit.

If the unit is to be part of a free standing stack, apply the pads to each marked corner area on the underside of the unit. Place the unit on top of the lower unit, ensuring that the pads locate with the recesses of the lower unit.

Positioning the Switch

When deciding where to position the Baseline 10/100 Switch 24 Port 10BASE-T/100BASE-TX plus 1-Port 1000BASE-T ensure:

It is accessible and cables can be connected easily.

Cabling is away from sources of electrical noise. These include lift shafts, microwave ovens, and air conditioning units. Elec- tromagnetic fields can interfere with the signals on copper cabling and introduce errors, therefore slowing down your network.

Water or moisture cannot enter the case of the unit.

Air flow around the unit and through the vents in the side of the case is not restricted (3Com recommend that you provide a minimum of 25mm (1in.) clearance).

TThe air is as free from dust as possible.

Temperature operating limits are not likely to be exceeded. It is recommended that the unit is installed in a clean, air condi- tioned environment.

It is always good practice to wear an anti-static wrist strap when installing network equipment, connected to a ground point. If one is not available, try to keep in con- tact with a grounded rack and avoid touching the unit's ports and connectors, if possible. Static discharge can cause reliability problems in your equipment.

Rack Mounting or Free Standing

The unit can be mounted in a 19-inch equipment rack using the Mounting Kit. Refer to “Mounting Kit Instructions” on page 4, or it can be free standing. Do not place objects on top of the unit or stack.

CAUTION: If installing the Baseline 10/100 Switch 24 Port 10BASE-T/100BASE-TX plus 1-Port 1000BASE-T in a free standing stack of different size SuperStack 3 units, the smaller units must be installed above the larger ones. Do not have a free standing stack of more than six units.

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.

3Com 10BASE-T manual Installation Recommendations, Rear Panel Connections, Positioning the Switch

Models: 10BASE-T