Connectors and Cables

This appendix provides connector and cable descriptions for the following fixed ports on the switch:

• Switched 10BaseT RJ-45 ports

• Switched Ethernet AUI port

• Console port

For information on the Catalyst 2820 module ports, refer to the Catalyst 2820 Modules User Guide and the Catalyst 2820 ATM Modules Installation and Configuration Guide.

Switched 10BaseT RJ-45 Ports

The 10BaseT RJ-45 ports (1x through 24x), as illustrated in Figure B-1, use the pin assignments described in Table B-1.

Figure B-1: 10BaseT RJ-45 Port

Table B-1: 10BaseT RJ-45 Port Pin Assignments

Pin	Label
1	RD+
2	RD-
3	TD+
4	NC
5	NC
6	TD-
7	NC
8	NC

As indicated by the X, the 10BaseT ports have their transmit (TD) and receive (RD) signals internally crossed for attachment of an adapter using a straight-through cable.

When connecting the 10BaseT ports to 10BaseT-compatible servers and workstations, ensure that you use a straight-through cable wired for 10BaseT. When connecting to other switches or repeaters, ensure that you use a crossover cable.

When connecting the Catalyst 2820 100BaseT module ports to 100BaseT-compatible servers and workstations, ensure that you use a straight-through cable. When connecting to the 100BaseT port on another switch, hub, or router, ensure that you use a crossover cable.

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Note Always observe the following general rules when connecting devices: Use a straight-through cable to connect two ports when one of the ports is designated with an X; use a crossover cable to connect two ports when both ports are designated with an X.

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The schematics of crossover and straight-through cables are shown in Figure B-2 and Figure B-3, respectively.

Figure B-2: Crossover Cable Schematic


Figure B-3: Straight-Through Cable Schematic

Switched Ethernet AUI Port

The Ethernet AUI port uses a 15-pin female connector, as shown in Figure B-4. The pin assignments for this port are described in Table B-2.

Figure B-4: Ethernet AUI Port

Table B-2: Ethernet AUI Port Pin Assignments

Pin	Label	Description
1	GND	Ground
2	CI+	Positive AUI differential collision-data input
3	TX+	Positive AUI differential transmit-data input
4	GND	Ground
5	RX+	Positive AUI differential receive-data output
6	GND	Ground
7	NC	--
8	GND	Ground
9	CI-	Negative AUI differential collision data
10	TX-	Negative AUI differential transmit-data input
11	GND	Ground
12	RX-	Negative AUI differential receive data output
13	+12V	12V supply for external MAU
14	GND	Ground
15	NC	--

Console Port

The console port uses an 8-pin RJ-45 connector, as shown in Figure B-1. The supplied RJ-45-to-RJ-45 rollover cable and adapters are used to connect the console port of the switch to a management station or modem. The following sections describe the rollover cable and adapters for the console port.

Identifying a Rollover Cable

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-5).

Figure B-5: Identifying a Rollover Cable

Connecting to a PC

Use the thin, flat, RJ-45-to-RJ-45 rollover cable and RJ-45-to-DB-9 female DTE adapter (labeled "TERMINAL") to connect the console port to a PC running terminal emulation software. Figure B-6 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").

Figure B-6: Connecting the Console Port to a PC

Table B-3: Console Port Signaling and Cabling Using a DB-9 Adapter

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

Connecting to a Terminal

Use the thin, flat, RJ-45-to-RJ-45 rollover cable and RJ-45-to-DB-25 female DTE adapter (labeled "TERMINAL") to connect the console port to a terminal. Figure B-7 shows how to connect the console port to a terminal. Table B-4 lists the pin assignments for the console port, the RJ-45-to-RJ-45 rollover cable, and the RJ-45-to-DB-25 female DTE adapter (labeled "TERMINAL").

Figure B-7: Connecting the Console Port to a Terminal

Table B-4: Console Port Signaling and Cabling Using a DB-25 Adapter

Console Port (DTE)	RJ-45-to-RJ-45 Rollover Cable		RJ-45-to-DB-25 Terminal Adapter	Console Device
Signal	RJ-45 Pin	RJ-45 Pin	DB-25 Pin	Signal
RTS	11	8	5	CTS
DTR	2	7	6	DSR
TxD	3	6	3	RxD
GND	4	5	7	GND
GND	5	4	7	GND
RxD	6	3	2	TxD
DSR	7	2	20	DTR
CTS	81	1	4	RTS

Connecting to a Modem

Use the thin, flat, RJ-45-to-RJ-45 rollover cable and RJ-45-to-DB-25 male DCE adapter (labeled "MODEM") to connect the console port to a modem. Figure B-8 shows how to connect the console port to a modem. Table B-5 lists the pin assignments for the console port, the RJ-45-to-RJ-45 rollover cable, and the RJ-45-to-DB-25 male DCE adapter (labeled "MODEM").

Figure B-8: Connecting the Console Port to a Modem

Table B-5: Console Port Signaling and Cabling Using a DB-25 Adapter

Console Port (DTE)	RJ-45-to-RJ-45 Rollover Cable		RJ-45-to-DB-25 Modem Adapter	Modem
Signal	RJ-45 Pin	RJ-45 Pin	DB-25 Pin	Signal
RTS	11	8	4	RTS
DTR	2	7	20	DTR
TxD	3	6	3	TxD
GND	4	5	7	GND
GND	5	4	7	GND
RxD	6	3	2	RxD
DSR	7	2	8	DCD
CTS	81	1	5	CTS