Attaching a Compact Serial Cable

To continue your Cisco PA-8T-232 port adapter installation, you must attach a compact serial cable to the port adapter. The instructions that follow apply to all supported platforms. This chapter contains the following sections:

•Connecting a Compact Serial Cable

•Determining the Port Mode

Connecting a Compact Serial Cable

On a single PA-8T-232, you can use only one EIA/TIA-232 compact serial cable, which is available only from Cisco Systems; it is not available from outside commercial cable vendors.

Caution Attach only an EIA/TIA-232 compact serial cable to the PA-8T-232 installed in your router. Attaching a compact serial cable of another interface type to the port adapter could damage your router or the hardware at the network end of the cable.

To connect a compact serial cable to a PA-8T-232, follow these steps:

Step 1 Attach the compact serial cable plug directly to the receptacle on the PA-8T-232, and tighten the strain-relief screws. (See Figure 4-1.)

Note Port adapters have a handle attached, but this handle is not shown to allow a full view of detail on each port adapter's faceplate.

When attaching the cable receptacle on the PA-8T-232, use the cable-management bracket that shipped with your router for extra strain relief.

Figure 4-1 Connecting a Compact Serial Cable—Front View Shown Without Handle

Caution Compact serial cables must be attached correctly, or damage to the cable plug results. Attempting to force a cable plug on the 200-pin receptacle can damage the plug. (See  Figure 4-2.)

Figure 4-2 Connecting the Compact Serial Cable

Step 2 Attach the network end of your compact serial cable to your DSU, CSU, DTE, or other external synchronous-serial equipment and tighten the strain-relief screws.

This completes the procedure for attaching a compact serial cable to the PA-8T-232.

If you need to replace a compact serial cable with a cable of a different mode (DTE or DCE), proceed to the "Determining the Port Mode" section; otherwise proceed to "Configuring the PA-8T-232 Interfaces."

Determining the Port Mode

The compact serial cable connected to each port determines the mode of the ports (the electrical interface type is always EIA/TIA-232). The default mode of the ports is DCE, which allows you to perform a loopback test on any port without having to attach a port adapter cable. For information related to the loopback command, see the "Using loopback Commands" section. Although DCE is the default, there is no default clock rate set on the interfaces. On a Cisco 7100 series, Cisco 7200 series, Cisco uBR7200 series router, Cisco 7301 routers, or Cisco 7401ASR router, when there is no cable attached to a port, the software actually identifies the port as cable type: None present rather than either a DTE or a DCE interface. On a Cisco 7304 PCI Port Adapter Carrier Card, VIP, Catalyst RSM/VIP2, or Catalyst 6000 family FlexWAN module, when there is no cable attached to a port, the software actually identifies the port as Universal (cable unattached) rather than either a DTE or a DCE interface.

Caution Attach only an EIA/TIA-232 compact serial cable to the PA-8T-232 installed in your router. Attaching a compact serial cable of another interface type to the port adapter could damage your router or the hardware at the network end of the cable.

Following is an example of the show controllers serial command that shows a Cisco 7100 series router, a Cisco 7200 series router, a Cisco uBR7200 series router, Cisco 7301 router, or a Cisco 7401ASR router interface port (1/0) that has a DCE cable attached: 

Router# show controllers serial 1/0


M8T-232: show controller:

PAS unit 0, subunit 0, f/w version 1-19, Rev id 0x2800001, version 2

idb = 0x60942688, ds = 0x608A6570, ssb=0x608C6CF0

Clock mux=0x0, ucmd_ctrl=0x1C, port_status=0xC

maxdgram=1524, bufpool=32Kb, 64 particles

     DCD=up  DSR=up  DTR=down  RTS=down  CTS=up

line state: down

cable type: RS232 DCE cable, received clockrate 123984

[display text omitted]

Following is an example of the show controllers cbus command that shows a VIP interface port (2/1/0) that has a DTE cable attached: 

Router# show controllers cbus


slot2: VIP2, hw 2.2, sw 21.40, ccb 5800FFA0, cmdq 480000C0, vps 8192

    software loaded from flash slot0:muck/amcrae/vip2_21-40.mxt

    FLASH ROM version 255.255

   Mueslix Serial(8), HW Revision 0x1, FW Revision 1.20

    Serial2/1/0, applique is RS232 DTE

      gfreeq 48000140, lfreeq 480001B0 (1536 bytes), throttled 0

      rxlo 4, rxhi 90, rxcurr 0, maxrxcurr 0

txq 48001A80, txacc 48001A82 (value 58), txlimit 58

[display text omitted]

To change the mode of a port online, use software commands to shut down the interface, replace the compact serial cable, restart the interface, and (if necessary) reconfigure the port for the new interface. At system startup or restart, the system polls the interfaces and determines the electrical interface type of each port (according to the type of compact serial cable attached). However, the system does not necessarily repoll an interface when you change the adapter cable online. To ensure that the system recognizes the new interface type, shut down and re enable the interface after changing the cable.

If you are replacing a cable with a cable that has the same mode, these steps are not necessary (simply replace the cable without interrupting operation).

Step 1 Enter configuration mode. At the privileged level of the EXEC, specify the port address and shut down the interface. (See the "Using the EXEC Command Interpreter" section for an explanation of the privileged level of the EXEC.)

•For a Catalyst RSM/VIP2, use the following example: 

Router> enable

Password: 

Router# configure terminal

Enter configuration commands, one per line. End with CNTL/Z.

Router(config)# interface serial 1/0

Router(config-if)# shutdown

Ctrl-Z

Router#

•For a Cisco 7100 series router, use the following example: 

Router> enable

Password: 

Router# configure terminal

Enter configuration commands, one per line. End with CNTL/Z.

Router(config)# interface serial 4/0

Router(config-if)# shutdown

Ctrl-Z

Router#

Note The preceding example is for Cisco 7140 series routers. For Cisco 7120 series routers, substitute 3 for 4 for the port adapter slot number in the interface address (3/0 in the example).

•For a Cisco 7200 series router, use the following example: 

Router> enable

Password: 

Router# configure terminal

Enter configuration commands, one per line. End with CNTL/Z.

Router(config)# interface serial 2/0

Router(config-if)# shutdown

Ctrl-Z

Router#

•For a Cisco 7301 router, use the following example: 

Router> enable

Password: 

Router# configure terminal

Enter configuration commands, one per line. End with CNTL/Z.

Router(config)# interface serial 1/0

Router(config-if)# shutdown

Ctrl-Z

Router#

Note For the Cisco 7301 router, the port adapter slot number is always 1.


•For a Cisco 7401ASR router, use the following example: 

Router> enable

Password: 

Router# configure terminal

Enter configuration commands, one per line. End with CNTL/Z.

Router(config)# interface serial 1/0

Router(config-if)# shutdown

Ctrl-Z

Router#

Note For the Cisco 7401ASR router, the port adapter slot number is always 1.

•For a Cisco uBR7200 series router, use the following example: 

Router> enable

Password: 

Router# configure terminal

Enter configuration commands, one per line. End with CNTL/Z.

Router(config)# interface serial 1/0

Router(config-if)# shutdown

Ctrl-Z

Router#

Note For the Cisco uBR7223 router, the port adapter slot number is always 1. For the Cisco uBR7246 router, the port adapter slot number is always 1 or 2.

•For a VIP, use the following example: 

Router> enable

Password: 

Router# configure terminal

Enter configuration commands, one per line. End with CNTL/Z.

Router(config)# interface serial 3/1/0

Router(config-if)# shutdown

Ctrl-Z

Router#

Step 2 Locate and remove the adapter cable to be replaced.

Step 3 Connect the new cable between the PA-8T-232 and the network connection. Tighten the thumbscrews at both ends of the cable to secure it in the ports.

Step 4 Enter configuration mode again, bring the port back up, and save the running configuration to NVRAM.

•For a Catalyst RSM/VIP2, use the following example: 

Router# configure terminal

Enter configuration commands, one per line. End with CNTL/Z.

Router(config)# interface serial 1/0

Router(config-if)# no shutdown

Ctrl-Z

Router#


Router# copy running-config startup-config

•For a Cisco 7100 series router, use the following example: 

Router> enable

Password: 

Router# configure terminal

Enter configuration commands, one per line. End with CNTL/Z.

Router(config)# interface serial 4/0

Router(config-if)# no shutdown

Ctrl-Z

Router#


Router# copy running-config startup-config

Note The preceding example is for Cisco 7140 series routers. For Cisco 7120 series routers, substitute 3 for 4 for the port adapter slot number in the interface address (3/0 in the example).

•For a Cisco 7200 series router, use the following example: 

Router> enable

Password: 

Router# configure terminal

Enter configuration commands, one per line. End with CNTL/Z.

Router(config)# interface serial 2/0

Router(config-if)# no shutdown

Ctrl-Z

Router#


Router# copy running-config startup-config

•For a Cisco 7301 router, use the following example: 

Router> enable

Password: 

Router# configure terminal

Enter configuration commands, one per line. End with CNTL/Z.

Router(config)# interface serial 1/0

Router(config-if)# no shutdown

Ctrl-Z

Router#


Router# copy running-config startup-config

Note For the Cisco 7301 router, the port adapter slot number is always 1.

•For a Cisco 7401ASR router, use the following example: 

Router> enable

Password: 

Router# configure terminal

Enter configuration commands, one per line. End with CNTL/Z.

Router(config)# interface serial 1/0

Router(config-if)# no shutdown

Ctrl-Z

Router#


Router# copy running-config startup-config

Note For the Cisco 7401ASR router, the port adapter slot number is always 1.

•For a Cisco uBR7200 series router, use the following example: 

Router> enable

Password: 

Router# configure terminal

Enter configuration commands, one per line. End with CNTL/Z.

Router(config)# interface serial 1/0

Router(config-if)# no shutdown

Ctrl-Z

Router#


Router# copy running-config startup-config

Note For the Cisco uBR7223 router, the port adapter slot number is always 1. For the Cisco uBR7246 router, the port adapter slot number is always 1 or 2.

•For a VIP, use the following example: 

Router# configure terminal

Enter configuration commands, one per line. End with CNTL/Z.

Router(config)# interface serial 1/0/0

Router(config-if)# no shutdown

Ctrl-Z

Router#


Router# copy running-config startup-config

These steps prompt the system to poll the interface and recognize the new interface immediately.

When you configure a port for a DCE interface for the first time, or when you set up a loopback test, you must set the clock rate for the port. When you connect a DCE cable to a port, the interface remains down and does not function until you set a clock rate (regardless of the DCE mode default).

If you are changing the mode of the interface from DCE to DTE, you do not need to change the clock rate for the port. After you replace the DCE cable with a DTE cable, and the system recognizes the interface as a DTE, it uses the external clock signal from the remote DCE device and ignores the internal clock signal that the DCE interface normally uses. Therefore, when you configure the clock rate on a port for either a DCE interface or loopback, you can leave the clock rate configured and still use that port as a DTE interface.

This completes the procedure for replacing a PA-8T-232 compact serial cable on the PA-8T-232. Proceed to "Configuring the PA-8T-232 Interfaces."