Rs 288-5796 Manual

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Operating environment

Ambient temperature: 32°F to 122°F (0°C to 50°C)

storage temperature: -20°C to 60°C

Ambient relative humidity: 10% to 95% (non-condensing)

Power supply (internal)

AC power connector: IEC-type, male recessed, rear of chassis

Power input voltage: 90 to 260 Vac (auto ranging)

Power input frequency: 47-63 Hz

Power consumption: 20 watts max.

Network cable connectors - for the eight RJ-45 shielded female ports per hub

100Mbps: Category 5 UTP/STP

10Mbps: Category 3, 4, 5 UTP (Note:Speed-sensing does not sense cable type)

Stackable cable - stacking may be up to four hubs, or ports

A stacking cable with 50-pin “SCSI” male connectors, shielded, 9 inches (23cm)

long, is included with each Magnum DS8-A dual-speed add-on unit.

Switch manual

UP-LINK: MDI-X thumb-operated slide switch, converts RJ-45 port 8 from a regular

(=position) user segment port to a crossover (X position) up-link port for On/off con-

nection to a central hub or another cascaded hub. The up-link port is auto-sensing for

speed, and the up-link works the same at 10Mbps or 100Mbps.

Packaging

Enclosure: High strength metal. Metal mounting brackets included.

Suitable for wiring closet shelf, wall or desktop mounting.

Dimensions: 9.75in. D x 8.5in. W x 1.4in. 11 (25cm x 22cm x 3.5cm)

Weight: 2.5lb. (1.15Kg)

Cooling method: Fan cooled, internal @ 9cfm

Agency approvals

UL listed (UL 1950), cUL, CE

Emissions: Meets FCC part 15, class A

Warranty

Three years, return to factory

Federal communication commission

Radio frequency interference statement

This equipment generates, uses and can radiate frequency energy and if not installed and used

properly, that is in strict accordance with the manufacturers instruction, may cause interference

to radio communication. It has been tested and found to comply with the limits for a Class A

computing device in accordance with the specifications in Subpart J of part 15 of ECC rules,

which are designed to provide reasonable protection against such interference when operated

in a commercial environment. Operation of this equipment in a residential area is likely to

cause interference, in which case the user at his own expense will be required to take whatever

measures may be required to correct the interference.

8 Port Hub DS8-A RS stock no. 288-5796

8 Port Hub DS8-B RS stock no. 288-5803

Issued March 1998 10771

Dual Speed

Stackable Hubs

Instruction Leaflet

Table of contents

1.0 Introduction __________________________________________________2

1.1 Inspecting the package and product ______________________________________2

1.2 Features and benefits ____________________________________________________2

1.3 Product description ____________________________________________________2

1.4 Stacking the hubs ______________________________________________________4

1.5 Bridge module ________________________________________________________4

1.6 Up-link switch for cascading ______________________________________________5

1.7 Applications____________________________________________________________5

2.0 Installation ____________________________________________________7

2.1 Locating the dual-speed hubs ____________________________________________7

2.1.1 Table top or shelf mounting ________________________________________7

2.1.2 Wall (or vertical surface) mounting__________________________________7

2.2 Connecting Ethernet Media ______________________________________________7

2.3 Powering the Hubs ______________________________________________________8

3.0 Operation ____________________________________________________8

3.1 Dual-speed functionality ________________________________________________8

3.2 Auto-negotiation and speed-sensing ______________________________________9

3.3 LED description ________________________________________________________9

3.4 Up-link switch ________________________________________________________10

4.0 Troubleshooting ______________________________________________10

4.1 Before calling for assistance ____________________________________________10

4.2 When calling for assistance______________________________________________11

5.0 Technical Specification ________________________________________11

The information provided in RS technical literature is believed to be accurate and reliable; however, RS

Components assumes no responsibility for inaccuracies or omissions, or for the use of this information, and all use

of such information shall be entirely at the user’s own risk.

No responsibility is assumed by RS Components for any infringements of patents or other rights of third parties

which may result from its use.

Specifications shown in RS Components technical literature are subject to change without notice.

RS Components, PO Box 99, Corby, Northants, NN17 9RS Telephone: 01536 201234

An Electrocomponents Company © RS Components 1997

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4.2 When calling for assistance

Please be prepared to provide the following information.

1. A complete description of the problem, including the following points:

a) The nature and duration of the problem

b) Situations when the problem occurs

c) The components involved in the problem

d) Any particular application that when used, appears to create the problem

2. An accurate list of the RS product model(s) involved, with serial number(s). Include the

date(s) that you purchased the product.

3. It is useful to include other network equipment models and related hardware, includ-

ing personal computers, workstations, terminals and printers, plus the various network

media types being used.

4. A record of changes that have been made to your network configuration prior to the

occurrence of the problem. any changes to system administration procedures should

all be noted in this record.

Important: RS Dual-speed hubs contain no user serviceable parts. Attempted service by

unauthorised personnel shall render any and all warranties null and void.

5.0 Specification

The RS dual speed stackable hubs support two traffic domains, one at 100Mbps and one

at 100Mbps and one at 10Mbps. Each hubs has ports, and and are stackable up to 4 units

high operating as one repeater.

Performance

When a port is operating at 100Mbps

PDV (Path delay value): 80BT, exceeds class 11

When a port is operating at 10Mbps

Date rate: 100Mbps

PDV (path delay value): 80BT, exceeds class 11

When a port is operating at 10Mbps

Data rate: 10Mbps

Partitioning: Enforced after 63 consecutive collisions

Auto-reconnect: Occurs after one packet of error-free reception

Network standards

Ethernet IEEE 802.3u, 100BASE-TX

Ethernet IEEE 802.3, 10BASE-T

Packet-processing between domains (internal 10/100 switch or bridge)

Filtering and forwarding rate from 100Mbps ports: 148,800 pps max.

Filtering and forwarding rate from 10Mbps ports: 14,880 pps max.

Processing type: Store and forward

Auto-learning: 8K address table, shared for both traffic domains

Packet buffers: 2MB, dynamically allocated and shared on both domains

Latency (not included packet time): 100 to 10Mbps: 5µs

10 to 100Mbps: 5µs

CPU type: State machine

Maximum Ethernet segment (or domain) lengths

10BASE-T (unshielded twisted pair) -100m (328ft)

100BASE-TX (CAT 5 UTP) -100m (328ft)

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1.0 Introduction

1.1 Inspecting the package and product

Inspect the contents of this package for any signs of damage and ensure that the items list-

ed below are included.

This package should contain:

1 DS8A or DS8B dual-speed hub

1 AC power cord

1 Stacking cable, (DS8A only)

1 Installation and user guide

1.2 Feature and benefits

●Supports 10 or 100Mbps network connections on each port

The RS dual-speed hubs combine two logical hubs, one at 10Mbps and one at 100Mbps,

in a single unit supporting two traffic domains. Each port can operate at either 10 or

100Mbps independently of the other ports.

●Auto-sensing for speed

All ports support 10/100 auto-negotiation for speed, operating separately on each port.

Any mix of 10Mbps and 100Mbps users can be connected to the ports. Individual ports

can change to 10Mbps or 100Mbps speed at any time, adapting automatically to any

changes in the connected devices speed. Speed-sensing complies with IEEE 802.3u, pro-

viding inter-operability with other products.

●An internal switch connects the 10 and 100Mbps domains on model DS8-B

Model DS8-B has an internal switch for filtering/forwarding traffic between the 10 and

100Mbps domains, allowing all connected devices to talk to each other. High performance

switching provides full bandwidth in each domain, unaffected by local traffic on the other

domain. One DS8-B per stack supports switching for all ports.

●Stackable for flexible expansion

The hubs can be stacked up to four units high or up to 32 ports, each 10/100 dual speed.

As additional units are added in a stack, the 10 and 100Mbps traffic domains are expand-

ed automatically to support the new ports at either 10 or 100Mbps speed.

●Transparent operation

Model DS8-B hub operates as a hardware switch, only forwarding those packets from each

domain that are needed on the other domain. Internal address tables are self-learning,

enabling users to change port connections or 10/100 domains without affecting operations.

The switch in the DS8-B will not affect any standard software applications or SNMP network

management platforms.

●Small enclosure enables use in offices and labs

The compact packaging of the hubs allows them to be installed in offices and labs, or vir-

tually any location within reach of a standard AC wall outlet. They come in a durable metal

enclosure for table-top or wall-mounting.

1.3 Product description - general

The RS dual-speed hubs have eight RJ-45 ports, each 10/100Mbps auto-sensing. Each port

can independently identify (via IEEE 802.3u auto-sensing) and accept either 10Mbps or

100Mbps Ethernet signals, adapting to match the best speed of the connected device.

There are two internal traffic domains, one for the 10Mbps traffic and one for the 100Mbps

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COL: Two collision LEDs one for each traffic domain, 10 and 100Mbps

Blinks intermittently when a collision occurs

ACT: Activity (send or receive) for each traffic domain, 10 and 100Mbps

100: Speed LED, per port. Flashing when auto-negotiating (no LINK)

ON when the port speed is 100Mbps, OFF for 10Mbps

LK: LINK LED, per port. Illuminates GREEN when a working connection is established

between the port and the attached device.

RX: Activity LED, per port. Flashes GREEN to indicate that the port is receiving data

from the attached device. i.e. there is activity on the port.

3.4 Up-link switch

The hubs have one up-link switch, used with port 8. This allows

repeater-to-repeater connection without a special cross-over cable. It

works the same for 10Mbps or 100Mbps connections.

Set the slide switch to the “=” position for twisted pair cabling from

the port to a user device, or to the “X” position for cross-over or up-

link segment connections from the port to a repeater or hub. Verify

proper switch position by noting the ports LINK LED status, which is

illuminated when a proper link is made.

4.0 Troubleshooting

All Ethernet products are designed to provide reliability and consistent high performance

in all network environments. The installation of a dual-speed hub is a simple procedure

(see installation); operation is easy and is described in section 3.0 Operation.

Should problems develop during installation or operation, this section should help to

locate, identify and correct such problems. Please follow the suggestions listed below prior

to contacting RS. However, if you are unsure of any procedure described in this section, or

if the hub is not operating as expected, do not attempt to repair or alter the unit. Contact

the RS Technical helpline for assistance.

4.1 Before calling for assistance

1. If difficulty is encountered when installing or operating the hubs refer to section 2.0

Installing and section 3.0, Operation. Check to make sure that the other devices of the net-

work are operating.

2. Check the cables and connectors to ensure that they have been properly connected and

the cables/wires have not been crimped or in some way impaired during installing.

3. Ensure the ac power cord is plugged into a functioning electrical outlet. Make sure that

the ac power cord is properly plugged into the hub. Use the PWR LED to verify the unit

is receiving proper power.

4. If the problem is isolated to a network device other than the dual-speed hub it is rec-

ommended that the problem device be replaced with a known good device. Verify

whether or not the problem is corrected. If not go to step 5 below. if the problem is cor-

rected, the hub and its associated cables are functioning properly.

5. If the problem continues after completing step 4 above, contact the RS technical helpline,

on Tel: 01536 402888 or fax: 01536 401588.

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traffic. The 10Mbps users share the 10Mbps domains bandwidth and the 100Mbps users

share the 100Mbps domains bandwidth. Functionally, the hubs operates as two hubs - one

hub at 10Mbps and one hub at 100Mbps - in one unit.

Any port can connect into either the 10Mbps or the 100Mpbs traffic domain, and can also

change from one traffic domain to the other at any time without affecting the speed of other

ports. The automatic per-port speed-sensing is continuous, allowing the connected

devices to change speed at any time without impairing the operation of the other ports and

connected devices.

As the dual-speed units are stacked, the two shared traffic domains automatically expand

to support all of the ports in the stack. Any combination of 10Mbps and 100Mbps ports, up

to the maximum of 32 ports (4units) in one stack, can be in use at any time.

The DS8-B model includes an internal bridge or switch module which interconnects the

10Mbps and the 100Mbps traffic domains. This enables all users on a DS8-B hub or a

stack, whether 10Mbps or 100Mbps, to talk to each other. The internal switch of the DS8-

B filters and selectively forwards packets between the 10Mbps and the 100Mbps domains,

maintaining peak performance in each domain unaffected by local traffic in the outer

domain. The internal bridge is self-learning, with large address table capacity for up to 8K

node addresses. As networked nodes are added or removed or move from one speed

domain to the other, the hubs internal switch automatically keeps track.

Only one DS8-B unit is needed to support a stack. Additional 8-port units of the DS8-A

hubs can be added to the stack, up to the 4-unit stack maximum. In a stack, the DS8-B unit

can be in any stack position.

DS8-A units can also be used without a DS8-B, whereupon they will function as dual-speed

stackable hubs. This could be desired if there is an external non-sensing switch available

to interconnect the two speed domains, or if only 100Mbps devices are connected and the

10Mbps domain is unused (or vice-versa), or if dual-speed operation with two unconnect-

ed and unco-ordinated domains is needed for the application.

Each hubs has its own internal power supply, and is easily added to an existing 10 or

100Mbps network. the dual-speed hubs are suitable for wiring closet shelf, table-top or

vertical mounting.

The hub chassis houses one main PC board, a bridge module daughter-board in the

model DS8-B, and an internal power supply unit. The front side of the chassis has eight RJ-

45 twisted-pair ports and one cascading(UP-LINK) switch for port 8.

LEDs to indicate operating status are on the front left side. There are power (PWR) and

bridge-inside (BR) indicators for the unit. There are activity (ACT) and collision (COL) indi-

cators for each of the 10Mbps and 100Mbps domains, set into a “square” arrangement, for

visual indication of the operating status of each domain and there are link (LK), receive (RX)

and speed (100) indicators for each port. The unit has a cooling fan on the bottom left cor-

ner which sends warm air out away from the unit to the rear. Stacking cables connect in the

rear.

The AC power cord connector, a universal recessed male IEC type connector is situated

on the rear of the chassis. The internal power supply is auto-ranging for AC power input of

110 to 230Vac. 50 - 60 Hz.

UP LINK

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1.4 Stacking the hubs

Up to four hubs can be stacked to operate as one 10/100 dual-speed repeater with up to

32 dual-speed ports. One DS8-B hub per stack is needed to provide a switched intercon-

nection between the two separate 100Mbps and 10Mbps traffic domains in the stack. addi-

tional stacked units can be model DS8-A hubs.

The DS8-B models with the bridge module inside look the same as the DS8-A units (no

bridge inside). The “BR” LED on the front will light up when power is applied to indicate

that a bridge module is installed. (The “BR” LED will be off if the unit is a model DS8-A).

The DS8-B models cannot be stacked together, as their internal bridges would not be able

to function properly when more than one is present. Use DS8-B models un-stacked, or with

only 1 model DS8-B in a DS8 stack.

When stacking the units make sure to use only the shielded 9-inch long stacking cable pro-

vided with each DS8-A unit. The cable length is designed to provide proper operation of

up to four units in a stack, and longer cables or unshielded cables are not permitted as they

will not operate properly at 100Mbps speeds.

The 9-inch length is enough to provide for side-by-side stacking. This can be convenient

when locating the units in a rack, for example, as two DS8 hubs will fit side-by-side on a

tray in a standard 19” rack space.

When connecting DS8 hubs in a stack, use the stacking cable to connect the “Out” stack-

ing port from one unit to the “In” stacking port of the other. Push in the cable connectors

until they snap in firmly. Also, leave space in the left-rear area for the exhaust of the inter-

nal cooling fan in each unit.

1.5 Bridge module (model DS8-B)

The DS8-B hubs contain a factory-installed bridge module to interconnect the two traffic

domains, filtering and selectively forwarding packets to allow necessary packets to cross

between the domains. This enables all of the users and modules connected into either

domain, whether 100Mbps or 10Mbps to talk to each other and it keeps local traffic on one

domain from consuming any of the bandwidth of the other domain.

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Packet Source Destination Address table Filter/forward

source address address maintenance action

10Mb Not in table Not in table Add source to table Forward

10Mb Not in table In table Add source to table Filter

10Mb In table Not in table None Forward

10Mb In table In table None Filter

100Mb Not in table Not in table Add source to table Forward

100mb Not in table In table Add source to table Filter

100Mb In table Not in table None Forward

100Mb In table In table None Filter

2. Address learning (address table maintenance)

The DS8-B bridge module is a state machine design which has a total address table capac-

ity of 8K addresses. With a large address table, a dual-speed hub can serve the needs of a

medium to large network. The table shows what filter/forward action the DS8-B hub will

take in each packet-processing situation, and when a new node address will be added to

the internal address table. When a new node-address packet comes into a port for the first

time, then the new source address is “learned” at the same time that the packet is for-

warded. After learning, subsequent packets from the same node address are routinely

processed. The address table are flushed periodically to update the network status and to

purge any inactive station from the tables of both domains.

3. Throughput increase

By selectively forwarding packets from each domain to the other domain based on its

switching (bridging) logic, the DS8-B hub increases the available bandwidth for the users

on both sides of the network. As shown in the table it keeps the local traffic on each side

contained, preventing unnecessary packets and bad packets from travelling to the other

domain and using up bandwidth needlessly over there. This results in more available net-

work bandwidth on both sides and the throughput increase for all users on both domains.

4. Software transparency

The RS dual-speed hubs need no software set-up and are transparent to system and appli-

cation software, including network management software.

3.2 Auto-negotiation and speed-sensing

All eight RJ-45 ports independently support auto-negotiation for shared 10BASE-T and

100BASE-TX modes. When the ‘100’ LED is flashing it means that the corresponding port

is sending out auto-negotiating pulses out of that port. When a connection is made, the

other device should respond and both sides should agree to the speed being detected.

Depending upon the device connected, it will either operate at 10Mb or 100Mb speeds.

Silence means the port defaults to 10mbps.

When the ‘100’ LED is ON, the port has auto-negotiated for 100Mbps operation and is pro-

cessing packets at 100Mbps.When it is OFF, it is at 10Mbps. If a port is connected to a non-

negotiating device, it will default to 10Mbps speed. The dual-speed will operate in the

shared or half-duplex mode on all ports.

3.3 LED Description

PWR: Illuminates GREEN to indicate ac power is applied to the unit

BR: Bridge module LED

ON when a bridge module is present in the unit (model DS8-B)

OFF when no bridge module is present (model DS8-A)

A. Fan exhaust

A. Bridge module

Figure 1

Figure 2

Note: Even though the connector is shielded, either unshielded or shielded cables

and wiring may be used.

2. Connect the other end of the cable to the corresponding device.

3. Use the LINK LED to ensure proper connectivity by noting that the LED will be illumi-

nated when the unit is powered and proper connection is established. For port 8, if the

LINK LED is not illuminated, change the setting of the up-link switch. If this does not

help, ensure that the cable is connected properly and that the device on the other end

is powered and is not defective.

2.3 Powering the hubs

The dual-speed hubs incorporates an internal universal power supply, and has a recessed

male IEC connector for the AC power cord in the rear. A 230Vac 50Hz power cord is sup-

plied with each unit.

The auto-ranging power supply supports installation environments where the ac voltage is

from 90 to 260 volts with an input frequency between 47 and 63Hz, and consumes a max-

imum of 20 watts. In order to power down the unit, simply unplug either end of the ac power

cable.

3.0 Operation

This chapter describes the function and operation of the dual-speed hubs.

3.1 Dual-speed functionality

The hubs handle the two different traffic domains separately (unless it is stacked with a

DS8-B). The DS8-B provides switched (bridged) connectivity between the ethernet

(10Mbps) and Fast ethernet (100Mbps) domains. It joins the two network domains for uni-

fied operation, and filters/forwards packets in both directions to maximise bandwidth util-

isation and performance. There is no software set-up to be done at installation or for main-

tenance.

Each time a packet is received on one domain of the bridge module, the decision is taken

to either filter or forward the packet. Error packets are always filtered. For good packets,

the filter and forward decisions are based on the destination address contained in each

packet. If the destination address is on the same domain from which the packet originated,

then it is filtered and not forwarded to the other domain. If the destination address is not

found to be a match in the address table for the originating domain, then it is forwarded to

the other domain. If it is a new node address coming in which the switch did not previous-

ly know about, it “learns” the new address and puts it in the correct port address table. See

“address learning” for more details.

This diagram below shows the filter/forward logic for both domains.

100Mb/s Domain : 100Mb/s packets are

forwarded when the destination address is

NOT in the 100Mb/s domain address table

10Mb/s Domain : 10Mb/s packets are

forwarded when the destination address is

NOT in the 10Mb/s domain address table

100Mb/s Domain : 100Mb/s packets are

forwarded when the destination address is

IS in the 100Mb/s domain address table

10Mb/s Domain : 10Mb/s packets are

forwarded when the destination address is

IS in the 10Mb/s domain address table

10 100

ABC

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The bridge operates in the store-and-forward mode which filters out bad packets and

maintains optimum performance in both domains. Packet forwarding delay is only 5µs

(plus packet time), much less than traditional store-and-forward bridge products enabling

the hubs to maintain high network performance. The bridge has 8K node address capac-

ity., suitable for use in large networks. Addresses are self-learning so that filtering/for-

warding of 10mbps and of 100Mbps packets is maintained correctly even when users

move their connection or change speed, or power down.

The DS8-B bridge module is implemented as a daughter board. The hub has an LED on

the front labelled ‘BR’ that will be ‘ON’ when the module is installed internally.

Note: Only one DS8 hub is allowed per repeater stack.

1.6 Up-link switch for cascading

The hubs have up-link switch for port 8, located on the front of the hub. It enables the ports

cable to either connect to a user station (= position) or to be cascaded to another hub (X

position) (see section 4.4 for more details about up-link). Like all ports, port 8 is a dual-

speed port which will sense the speed of the connected device. The up-link switch oper-

ates the same, whether port 8 is connected to either 10Mbps or 10Mbps devices.

When the up-link port is used to cascade two hubs or stacks together, the auto-sensing

feature will cause the connecting link to operate at 100Mbps speed.

1.7 Applications

Example 1:

A DS8-B hub serves a small office with mixed speed requirements. Some users operate at

100Mbps and some users and utility devices (such as print servers) run at 10Mbps. All share

the same hub, and talk to each other via the bridge module inside. Any node can change

speed at any time without affecting network operation or impacting other users.

Example 2:

Where there are existing 10Mbps hubs and users, they can easily be cascaded into any port

of the DS8-B. This allows simple plug-and-play addition of 100Mbps ports to an existing

10Mbps network without having to change it. Nodes that are capable of 100Mbps speed can

be moved to any dual-speed port, and will automatically operate at the higher speed. The

dual-speed ports on the DS8-B can be used for adding 100Mbps users or for accommodating

existing high performance users. The 100Mbps traffic does not use the bandwidth of the

10Mbps domain, so overall performance of the network is improved.

10100

100

ACT

COL

PWR BR

UPLINK

234 5678

ABC

A. 100 Server

B. 100 Users

C. 10 Users

D. Print server

E. Router

A. 10Mbps domain

B. 10 BUS 100

C. 10 BUS 10

Figure 3

Figure 6

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2.0 Installation

This chapter provides instructions for installing the RS dual-speed hubs.

2.1 Locating the dual-speed hubs

The location of a Dual-speed hub is dependent on the physical layout of the network.

Typically the hub is placed where combinations of 10Mbps and 100Mbps network devices

need to be connected to communicate with each other. The compact size of the unit allows

it to be conveniently placed in an office or lab area and can be either shelf or wall mount-

ed using the wall-mounting brackets supplied. The width of two units will fit in a 19” rack

when they are side-by-side.

Locate a mains socket that is within six feet (2 metres) of the selected location. The rugged

metal case of the hub will normally protect it from accidental damage in a lab or workplace

environment. Maintain an open view of the front to visually monitor the status LEDs. Keep

an open area around the unit so that cooling can occur from the fan in the bottom-rear

while the unit is in operation.

2.1.1 Table-top or shelf mounting

The RS dual-speed hub can be easily mounted on a table-top or any suitable horizontal

surface, and has four rubber feet to provide stability without scratching finished surfaces.

When stacked, the rubber feet also provide separation between units for the exhaust of the

rear cooling fan.

2.1.2 Wall (or vertical surface) mounting

Each dual-speed hub is shipped with two metal mounting brackets (and screws) to allow

the unit to be mounted in most of the desired orientation or position. The brackets are

attached to the metal hub case using one of the metal screws for each bracket and attach-

ing to the hub through the round hole of the bracket. A user-supplied screw attaches the

bracket to the mounting surfaces. it is recommended that the brackets are attached to two

opposite corners of the unit. When properly attached, the brackets will extend slightly

below the base of the unit to allow clearance for the rubber feet and the cooling fan

exhaust.

2.2 Connecting Ethernet media

The dual-speed stackable hubs can be connected to the following two media types:

100BASE-TX and 10BASE-T. CAT 5 cables should be used when making 100BASE-TX

connections. When the ports are used as 10BASE-T ports, CAT 3 may be used. In either

case, the maximum distance for unshielded twisted pair cabling is 100 meters (3287ft).

Media IEEE standard Connector

Twisted pair (CAT 3) 10BASE-T RJ-45

Twisted pair (CAT 5) 100BASE-TX RJ-45

Note: It is recommended that high quality CAT 5 cables (which work for both 10Mbps

and 100Mbps) be used whenever possible in order to provide flexibility in a

mixed-speed network, since dual-speed ports are auto-sensing for either 10 and

100Mbps.

2.2.1 Connecting twisted pair (RJ-45, CAT 3 or CAT 5, unshielded or shielded)

The following procedure describes how to connect a 10BASE-T or 100BASE-TX twisted

pair segment to the RJ-45 port. The procedure is the same for both unshielded and shield-

ed twisted pair cables.

1. Using standard twisted pair media, insert either end of the cable with an RJ-45 plug

into the RJ-45 connector of the port.

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Example 3:

For additional expansion, the hubs can be stacked using additional DS8-A units. The addition-

al stacked ports are all auto-sensing dual-speed, and can be used at either 10Mbps or

100Mbps.

The stacking cables connect the units and carry the signals for both the 100Mbps and the

10Mbps domains. In a stack, all 10Mbps ports operate in a 10Mbps traffic domain while all

100Mbps ports operate on a separate 100Mbps traffic domain. When one DS8-B unit with a

bridge inside is present in a stack, its bridge will support all of the ports in the stack and

enable network traffic to move between the two stacked domains.

A stack operates as one dual-speed repeater. A dual-speed repeater is both a 10Mbps hub

and a 100Mbps hub at the same time. This means that the 10Mbps traffic domain obeys all of

the rules of 10Mbps shared Ethernet networks (hop counts, cable types, cable distances, etc.)

and can be treated as one 10Mbps repeater accordingly. The 100Mbps traffic domain obeys

all of the rules of 100Mbps Fast Ethernet shared networks (hop counts, PDVs, cable types,

cable distances, etc.) and can be treated as one 100Mbps repeater. Both traffic domains func-

tion within the same physical hub or stack of hubs.

When you are expanding an Ethernet or Fast Ethernet network, the dual-speed hubs are

ideally suited for connecting servers and stations that have (or may have in the future)

mixed speeds. Each traffic domain or segment has its own local traffic with the DS8-B per-

forming bridge-isolation of one domain from the other, filtering and selectively forward-

ing 10Mbps and 100Mbps packets between the two domains. This keeps the traffic

between the domains to a minimum and provides peak performance on both domains.

10100

100

ACT

COL

PWR BR

UPLINK

234 5678

10100

100

ACT

COL

PWR BR

UPLINK

234 5678

10100

100

ACT

COL

PWR BR

UPLINK

234 5678

10100

100

ACT

COL

PWR BR

UPLINK

234 5678

10100

100

ACT

COL

PWR BR

UPLINK

234 5678

A. 100 Server

B. 100 Users

C. 10 Users

D. 10Mb hub

E. Print server

F. Router

A. 100 Server

B. 100 Users

C. 10 Users

D. 10Mb hub

E. Print server

F. Router

Figure 4

Figure 5