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This appendix provides connector and cable descriptions for the following ports on the hub:
This appendix also provides:
Table B-1 lists the 10/100 network and uplink ports on the FastHub 400 models.
| Model | Network Ports | Uplink Port |
|---|---|---|
FastHub 412 models | 1x through 12x | 12 |
FastHub 424 models | 1x through 24x | 24 |
The 10/100 network ports and 10/100 uplink port use standard RJ-45 connectors. Table B-2 lists the pinouts for these ports.
| Pin | Signal |
|---|---|
1 | RD+ |
2 | RD- |
3 | TD+ |
4 | NC |
5 | NC |
6 | TD- |
7 | NC |
8 | NC |
The 10/100 network ports are internally crossed (shown with an X next to each port number). Use an Ethernet crossover cable to connect these ports to other network devices, such as switches or other hubs. Use a straight-through cable to connect these ports to workstations, servers, or routers. Use the following types of cable, appropriately:
 | Caution When cabling an Ethernet network that contains autosensing 10/100 repeaters like the FastHub 400 series, use caution when using Category 3 and Category 4 cable. These cable types do not support 100BaseTX networks. |
The 10/100 uplink port is not internally crossed. Use an Ethernet crossover cable to connect this port to other network devices, such as workstations, servers, or routers. Use a straight-through cable to connect this port to switches or other hubs. Use the following types of cable, appropriately:
| Caution When cabling an Ethernet network that contains autosensing 10/100 repeaters like the FastHub 400 series, use caution when using Category 3 and Category 4 cable. These cable types do not support 100BaseTX networks. |
| Caution If you connect to both port 12x and 12 (or port 24x and 24), you will disable both ports. |
Figure B-1 is a schematic of the types of cable (straight-through and crossover) used to connect the hub to network devices.
The console port uses an 8-pin RJ-45 connector, as shown in Figure B-1. The supplied RJ-45-to-RJ-45 rollover console cable and adapter are used to connect the console port of the hub to a management station or modem. The following sections describe the supplied rollover console cable and adapter for the console port.
You can identify a rollover cable by comparing the two modular ends of the cable. Hold the cable ends side-by-side, with the tab at the back. The wire connected to the pin on the outside of the left plug should be the same color as the wire connected to the pin on the outside of the right plug (see Figure B-2).
Use the thin, flat, RJ-45-to-RJ-45 rollover console cable and RJ-45-to-DB-9 female DTE adapter (labeled TERMINAL) to connect the hub console port to a PC running terminal emulation software. Figure B-3 shows how to connect the console port to a PC. Table B-3 lists the pin assignments for the console port, the RJ-45-to-RJ-45 rollover cable, and the RJ-45-to-DB-9 female DTE adapter (labeled TERMINAL).
| Console Port (DTE) | RJ-45-to-RJ-45 Rollover Cable | RJ-45-to-DB-9 Terminal Adapter | Console Device | |
|---|---|---|---|---|
| Signal | RJ-45 Pin | RJ-45 Pin | DB-9 Pin | Signal |
RTS | 11 | 8 | 8 | CTS |
DTR | 2 | 7 | 6 | DSR |
TxD | 3 | 6 | 2 | RxD |
GND | 4 | 5 | 5 | GND |
GND | 5 | 4 | 5 | GND |
RxD | 6 | 3 | 3 | TxD |
DSR | 7 | 2 | 4 | DTR |
CTS | 81 | 1 | 7 | RTS |
| 1Pin 1 is connected (inside the terminal adapter) to Pin 8. |
This section provides cabling guidelines for building networks using the FastHub 400 series and other repeaters.
The IEEE 802.3u standard defines two different classes of Ethernet repeaters, Class I and Class II.
The FastHub 400 series are Class II repeaters with the following advantages:
Many switches have internal repeaters or plug-in repeater modules. In this type of device, the switch is actually attached to a port on the internal repeater. When connecting the hub to a switch, find out whether the port you are connecting to is a repeater port, and then take one of the following steps:
Table B-4 describes some guidelines when creating Ethernet networks with multiple repeaters. Exact figures could vary, depending on the manufacturer of the network equipment.
| Specification | 10BaseT | 100BaseTX |
|---|---|---|
Maximum segment length | 100 meters | 100 meters |
Maximum number of segments per network | 5 |
|
Maximum number of hops1 | 4 |
|
Maximum number of stations per segment | 1024 | 1024 |
Cable type supported | Category 3, 4, or 5 | Category 5 |
| 1Hops = other repeaters. |
The IEEE 802.3u standard specifies network configurations using Class II repeaters. These configurations were designed to satisfy the requirements of most networks that are built to the EIA/TIA-568 wiring standard. This standard specifies 100-meter Category 5 connections from wiring closets to desktops.
With only Category 5 cable segments, the maximum length for any cable segment is 100 meters, as shown in Figure B-4.
The example in Figure B-5 shows the hub connected to stations through its 10/100 ports and the optional 100BaseFX module port. The hub is also connected to a server through its 100BaseFX switched uplink module port. The maximum Category 5 cable segment length is 100 meters. The maximum fiber-cable segment length is 412 meters if the link is operating in half-duplex mode (2 kilometers in full duplex).
If all Category 5 cable segments connected to the FastHub unit are less than 100 meters, the length of the fiber-cable segment can be increased.
The maximum Category 5 cable segment length is 100 meters. When stations are connected to the FastHub units with 100-meter cable segments, the cable connecting the two FastHub units is limited to a distance of 5 meters, as shown in Figure B-6.
If all of the cable segments connecting stations to one or both of the FastHub units are less than 100 meters, the length of the cable segment connecting the two FastHub units can be increased.
You can increase the distance between two FastHub units by reducing the maximum cable segments connecting them to stations. The maximum Category 5 equivalent distance between any two stations separated by two FastHub units is 205 meters.
In the following example, you need to separate the two repeaters by 60 meters
(see Figure B-7). Using A + B + C = 205 meters and substituting 60 meters for segment B, we arrive at A + C £ 145 meters. Neither segment A or C can be greater than 100 meters.
You can increase the distance between two FastHub units by connecting them through their switched uplink modules (10BaseT/100BaseTX or 100BaseFX). As shown in Figure B-8, the maximum length for segment B is 100 meters for Category 5 and 412 meters for fiber in half-duplex mode (2 kilometers in full duplex). Segments A and C can be no greater than 100 meters.
Shielded twisted-pair cable is the most commonly used cable in Token-Ring environments. The media interface connectors (MICs) and baluns---used to connect shielded twisted-pair and unshielded twisted-pair cabling---create a loopback when they are disconnected; the loopback might cause anomalies with the hub.
To prevent loopback problems when using shielded twisted-pair cabling in a Token-Ring network environment, make sure the MICs and baluns are never left unconnected when they are part of a link connected to the hub (see Figure B-9).
Posted: Wed Feb 24 10:56:23 PST 1999
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