PA-8T-V35 Synchronous Serial Port Adapter Installation and Configuration

Figure 20 : Connecting a 8T-V.35 Compact Serial Cable (Front View---Shown without Handle)

Caution Compact serial cables must be attached correctly or damage to the cable plug will result. Attempting to force a cable plug on the 200-pin receptacle can damage the plug. Figure 21 shows the correct orientation of the compact serial cable to the 8T-V.35 port adapter.

Figure 21 : Connecting the Compact Serial Cable

Step 2 Attach the network end of your 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 an 8T-V.35 compact serial cable to the 8T-V.35 port adapter.

Replacing an 8T-V.35 Compact Serial Cable

The compact serial cable connected to each port determines the mode of the port (the electrical interface type is always V.35). The default mode of the ports is DCE, which allows you to perform a loopback test on any port without having to attach a compact serial cable. For information related to the loopback command, refer to the section "Using the ping Command" later in this document. Although DCE is the default, there is no default clock rate set on the interfaces. 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 DCE interface.

Caution Only attach a V.35 compact serial cable to the 8T-V.35 port adapter 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 command that shows an interface port (1/0) that has a V.35 DCE cable attached:

Router# sh cont serial 1/0

M8T-V.35: 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 : V.35 DCE cable, received clockrate 123984
[display text omitted]

To change the mode of a port online, you replace the compact serial cable and use software commands to restart the interface and, if necessary, reconfigure the port for the new interface. At system startup or restart, the network processing engine polls the interfaces and determines the electrical interface type of each port (according to the type of compact serial cable attached). However, it 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 reenable the interface after changing the cable.

Perform the following steps to change the mode of a port by replacing the compact serial cable. First shut down the interface, then replace the cable and bring up the interface with the new cable attached so that the system recognizes the new interface. (Refer to the section "Shutting Down an Interface" later in this document when shutting down an interface.) If you are replacing a cable with one of the same mode, these steps are not necessary (simply replace the cable without interrupting operation).

Step 1 At the privileged level of the EXEC, specify the port address, shut down the interface, and write the configuration to nonvolatile random-access memory (NVRAM). Add additional configuration commands, if any, before you exit from Configuration mode (before you enter Ctrl-Z).

Router> enable

Password:

Router# configure terminal

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

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

Router(config-int)# shutdown

Ctrl-Z

Router#

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

Step 3 Connect the new cable between the 8T-V.35 port adapter 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.

Router# configure terminal

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

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

Router(config-int)# no shutdown

Ctrl-Z

Router#

Router# copy running-config startup-config

These steps will prompt the system to poll the interface and recognize 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 will remain down, the clock LEDs will remain off, and the interface will 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 will use the external clock signal from the remote DCE device and ignore the internal clock signal that the DCE interface normally uses. Therefore, once 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 an 8T-V.35 compact serial cable on the 8T-V.35 port adapter.

Using the EXEC Command Interpreter

Before you use the configure command to configure the interfaces or change an existing configuration, you must enter the privileged level of the EXEC command interpreter with the enable command. The system will prompt you for a password if one has been set.

The system prompt for the privileged level ends with a pound sign (#) instead of an angle bracket (>). At the console terminal, enter the privileged level as follows:

Step 1 At the user-level EXEC prompt, enter the enable command. The EXEC prompts you for a privileged-level password, as follows:

Router> enable


Password:


Step 2 Enter the password (the password is case-sensitive). For security purposes, the password is not displayed.

Step 3 When you enter the correct password, the system displays the privileged-mode system prompt (#) as follows:

Router#

Proceed to the following section to configure the new interfaces.

Configuring the 8T-V.35 Interfaces

If you installed a new 8T-V.35 port adapter or if you want to change the configuration of an existing interface, you must enter Configuration mode to configure the new interfaces. If you replaced a 8T-V.35 port adapter that was previously configured, the system will recognize the new 8T-V.35 port adapter interfaces and bring each of them up in their existing configuration.

After you verify that the new 8T-V.35 port adapter is installed correctly (the enabled LED goes on), use the privileged-level configure command to configure the new interfaces. Be prepared with the information you will need, such as the following:

• Protocols you plan to route on each new interface
  

• Internet protocol (IP) addresses if you will configure the interfaces for IP routing
  

• Whether or not the new interfaces will use bridging
  

• Timing source for each new interface and clock speeds for external timing
  

For a summary of the configuration options available and instructions for configuring a serial interface on a Cisco 7200 series router, refer to the appropriate configuration publications listed in the section "If You Need More Information" on page 2.

The following sections describe the commands for configuring an external clock signal for a DCE interface and for configuring a port for NRZI encoding or 32-bit CRC. Configuration commands are executed from the privileged level of the EXEC command interpreter, which usually requires password access. (See the section "Shutting Down an Interface" on page 30.) Refer to the description that follows and contact your system administrator, if necessary, to obtain access.

Selecting Port Adapter Slot and Serial Interface Port Numbers

The following section describes how to identify port adapter slot and serial interface port numbers.

Physical port addresses specify the actual physical location of each interface port on the router. (See Figure 22.) This address is composed of a two-part number in the format port adapter slot number/interface port number, as follows:

• The first number identifies the chassis slot in which the 8T-V.35 port adapter is installed.
  

• The second number identifies the interface ports on each 8T-V.35 port adapter, which are always numbered in sequence as interface 0 through 7.
  

Interface ports on the 8T-V.35 port adapter maintain the same address regardless of whether other port adapters are installed or removed. However, when you move a port adapter to a different slot, the first number in the address changes to reflect the new slot number.

Figure 22 shows the interface ports of a 8T-V.35 port adapter in slot 1 of a Cisco 7206 router. The port adapter slot numbers start with 1 and continue through 6 for the Cisco 7206 and continue through 4 for the Cisco 7204 (slot 0 is always reserved for the Fast Ethernet port on the I/O controller---if present). The individual interface port numbers always begin with 0. The number of additional ports depends on the number of ports on a port adapter. Port adapters can occupy any port adapter slot. There are no restrictions.

For example, the addresses of the interface ports on the 8T-V.35 port adapter in chassis slot 1 are 1/0 through 1/7 (chassis slot 1 and interface ports 0 through 7). If the 8T-V.35 port adapter was in port adapter slot 4, these same interface ports would be numbered 4/0 through 4/7.

Figure 22 : Serial Interface Port Number Example

You can identify interface ports by physically checking the slot/port adapter/interface port location on the back of the router or by using software commands to display information about a specific interface or all interfaces in the router.

Shutting Down an Interface

Before you remove an interface that you will not replace, replace a compact serial cable, or replace port adapters, shut down (disable) the interfaces to prevent anomalies when you reinstall the new or reconfigured interface processor. When you shut down an interface, it is designated administratively down in the show command displays.

Follow these steps to shut down an interface:

Step 1 Enter the privileged level of the EXEC command interpreter. (Refer to an earlier section for instructions.)

Step 2 At the privileged-level prompt, enter Configuration mode and specify that the console terminal will be the source of the configuration subcommands, as follows:

Router# configure terminal

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

Router(config)#

Step 3 Specify the slot/port address of the first interface that you want shut down by entering the subcommand interface, followed by the type (serial) and slot/port (port adapter slot number/0). The example that follows is for a port adapter in slot 1:

Router(config)# interface serial 1/0

Step 4 Enter the shutdown command, as follows:

Router(config-int)# shutdown

Step 5 To shut down additional interfaces, enter the slot/port address of each additional interface followed by the shutdown command. When you have entered all the interfaces to be shut down, press Ctrl-Z (hold down the Control key while you press Z) to exit Configuration mode and return to the EXEC command interpreter prompt, as follows:

Router(config-int)# int serial 1/0

Router(config-int)# shutdown

Router(config-int)# int serial 1/1

Router(config-int)# shutdown

Ctrl-Z

Router#

Step 6 Write the new configuration to memory, as follows:

Router# copy running-config startup-config

[OK]

Router#

The system displays an OK message when the configuration has been stored.

Step 7 To verify that new interfaces are now in the correct state (shutdown), use the show interface serial slot/port command to display the specific interface, or use the show interfaces command, without variables, to display the status of all interfaces in the system.

Router# show int serial 1/0

Serial 1/0 is administratively down, line protocol is down

Hardware is M8T-V.35

[display text omitted]

Step 8 To reenable the interfaces, repeat the previous steps, but use the no shutdown command in Step 4, then write the new configuration to memory, as follows:

Router(config)# int serial 1/0

Router(config-int)# no shutdown

Ctrl-Z

Router#

Router# copy running-config startup-config

[OK]

Router# show int serial 1/0

Serial 1/0 is up, line protocol is up

Hardware is M8T-V.35

[display text omitted]

For complete descriptions of software configuration commands, refer to the publications listed in the section "If You Need More Information" on page 2.

Configuring Interfaces

Following are instructions for a basic interface configuration: enabling an interface, specifying IP routing, and setting up external timing on a DCE interface. You might also need to enter other configuration subcommands, depending on the requirements for your system configuration and the protocols you plan to route on the interface. For complete descriptions of configuration subcommands and the configuration options available for serial interfaces, refer to the appropriate software documentation.

Each 8T-V.35 port adapter contains four serial interfaces. The following steps describe a basic configuration. Press the Return key after each step unless otherwise noted. At any time you can exit the privileged level and return to the user level by entering disable at the prompt as follows:

Router# disable








Router> 

Following is an example of a basic configuration procedure:

Step 1 At the privileged-level prompt, enter Configuration mode and specify that the console terminal will be the source of the configuration subcommands, as follows:

Router# configure terminal

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

Router(config)#

Step 2 At the prompt, specify the first interface to configure by entering the subcommand interface, followed by the type (serial) and slot/interface (port adapter slot number and interface number). The example that follows is for the first interface of the first port adapter in slot 1:

Router(config)# interface serial 1/0

Step 3 If IP routing is enabled on the system, you can assign an IP address and subnet mask to the interface with the ip address configuration subcommand, as in the following example:

Router(config-int)# ip address 1.1.1.10

Step 4 Add any additional configuration subcommands required to enable routing protocols and set the interface characteristics.

Step 5 If you are configuring a DTE interface, proceed to Step 7. If you are configuring a DCE interface, you also need to configure the external clock signal, as described in the next step.

Step 6 Set the clock rate with the clock rate command. (See the section "Configuring Timing (Clock) Signals" on page 52.)

Router(config-int)# clock rate 72000

Step 7 Change the shutdown state to up and enable the interface as follows:

Router(config-int)# no shutdown

Step 8 Configure additional interfaces as required.

Step 9 When you have included all of the configuration subcommands to complete the configuration, press Ctrl-Z to exit Configuration mode.

Step 10 Write the new configuration to nonvolatile memory as follows:

Router# copy running-config startup-config

[OK]

Router#

This completes the procedure for creating a basic configuration.

Configuring Timing (Clock) Signals

All interfaces support both DTE and DCE mode, depending on the mode of the interface cable attached to the port. To use a port as a DTE interface, you need only connect a DTE compact serial cable to the port. When the system detects the DTE mode cable, it automatically uses the external timing signal. To use a port in DCE mode, you must connect a DCE interface cable and set the clock speed with the clock rate configuration command. You must also set the clock rate to perform a loopback test. This section describes how to set the clock rate on a DCE port and, if necessary, how to invert the clock to correct a phase shift between the data and clock signals.

Setting the Clock Rate

The default operation on an 8T-V.35 port adapter DCE interface is for the DCE device to generate its own clock signal (TxC) and send it to the remote DTE. The remote DTE device returns the clock signal to the DCE. The clock rate command specifies the rate as a bits-per-second value. In the following example, the clock rate for the serial interface on an 8T-V.35 port adapter in port adapter slot 1 (1/0) is defined as 72 kbps:

Router(config)# interface serial 1/0

Router(config-int)# clock rate 72000

Use the no clock rate command to remove the clock rate.

Following are the acceptable clockrate settings:

1200, 2400, 4800, 9600, 19200 38400 , 56000 , 64000 ,
72000 , 125000 148000 , 250000, 500000, 800000, 1000000,
1300000, 2000000, 4000000, 8000000

Inverting the Clock Signal

Systems that use long cables or cables that are not transmitting the TxC (clock) signal may experience high error rates when operating at the higher transmission speeds. If an 8T-V.35 port adapter DCE port is reporting a high number of error packets, a phase shift might be the problem. Inverting the clock may correct this shift.

When the 8T-V.35 port adapter interface is a DTE, the invert-txc command inverts the TxC signal it receives from the remote DCE. When the 8T-V.35 port adapter interface is a DCE, this command inverts the clock signal to the remote DTE port. Use the no invert-txc command to change the clock signal back to its original phase.

Inverting the Data Signal

If the interface on the 8T-V.35 synchronous serial port adapter is used to drive a dedicated T1 line that does not have B8ZS encoding (a method to avoid 15 zeros), the data stream must be inverted (both TXD and RXD) either in the connecting CSU/DSU or the interface. To invert the data stream coming out of the 8T-V.35 port adapter, use the invert data command.

By inverting the HDLC data stream, the HDLC zero insertion algorithm becomes a ones insertion algorithm that satisfies the T1 requirements. Be careful not to invert data both on the interface and on the CSU/DSU as two data inversions will cancel each other out.

Configuring NRZI Format

All 8T-V.35 interfaces support nonreturn-to-zero (NRZ) and nonreturn-to-zero inverted (NRZI) formats. Both formats use two different voltage levels for transmission. Both formats use two different voltage levels for transmission. NRZ signals maintain constant voltage levels with no signal transitions (no return to a zero voltage level) during a bit interval and are decoded using absolute values (0 and 1). NRZI uses the same constant signal levels but interprets the absence of data (a space) at the beginning of a bit interval as a signal transition and the presence of data (a mark) as no transition. NRZI uses relational encoding to decode signals rather than determining absolute values.

NRZ format, the factory default on all interfaces, is most common. NRZI format, which is configured with a software command, is commonly used with EIA/TIA-232 connections in IBM environments.

To enable NRZI encoding on any interface, specify the slot and port address of the interface followed by the command nrzi-encoding [mark]. Enter Ctrl-Z when you have finished with the configuration change. In the example that follows, the first serial port on an 8T-V.35 port adapter in port adapter slot 1 is configured for NRZI encoding:

Router# configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
Router(config)# interface serial 1/0
Router(config-int)# nrzi-encoding 
Ctrl-Z
Router# 

To disable NRZI encoding on a port, specify the slot and port address and use the no nrzi-encoding command. For complete command descriptions and instructions, refer to the related software documentation.

Configuring CRCs

CRC is an error-checking technique that uses a calculated numeric value to detect errors in transmitted data. All interfaces use a 16-bit CRC (CRC-CITT) by default, but also support a 32-bit CRC. The sender of a data frame calculates the frame check sequence (FCS). Before it sends a frame, the sender appends the FCS value to the message. The receiver recalculates the FCS and compares its calculation to the FCS from the sender. If there is a difference between the two calculations the receiver assumes that a transmission error occurred and sends a request to the sender to resend the frame.

The default for all serial interfaces is 16-bit CRC. To enable 32-bit CRC on an interface, specify the slot and port address of the interface followed by the command crc 32.

In the example that follows, the first serial port on an 8T-V.35 port adapter in slot 1 is configured for 32-bit CRC:

Router# configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
Router(config)# interface serial 1/1
Router(config-int)# crc 32 
Ctrl-Z
Router#

To disable CRC-32 and return to the default CRC-16 (CRC-CITT) setting, specify the slot and port address and use the no crc 32 command. For command descriptions, refer to the related software documentation.

Checking the Configuration

After configuring the new interface, use the show commands to display the status of the new interface or all interfaces, and use the ping and loopback commands to check connectivity.

Using show Commands to Verify the New Interface Status

The following steps use show commands to verify that the new interfaces are configured and operating correctly.

Step 1 Display the system hardware configuration with the show version command. Ensure that the list includes the new serial interfaces.

Step 2 Display all the current interface processors and their interfaces with the show controllers command. Verify that the new 8T-V.35 port adapter appears in the correct slot.

Step 3 Specify one of the new interfaces with the show interfaces port adapter type slot/interface command and verify that the first line of the display specifies the interface with the correct slot number. Also verify that the interface and line protocol are in the correct state: up or down.

Step 4 Display the protocols configured for the entire system and specific interfaces with the show protocols command. If necessary, return to Configuration mode to add or remove protocol routing on the system or specific interfaces.

Step 5 Display the running configuration file with the show running-config command. Display the configuration stored in NVRAM using the show startup-config command. Verify that the configuration is accurate for the system and each interface.

If the interface is down and you configured it as up, or if the displays indicate that the hardware is not functioning properly, ensure that the network interface is properly connected and terminated. If you still have problems bringing the interface up, contact a service representative for assistance.

Using show Commands to Display Interface Information

To display information about a specific interface, use the show interfaces command with the interface type and port address in the format show interfaces [type slot/port].

Following is an example of how the show interfaces [type slot/port] command displays status information (including the physical slot and port address) for the interface you specify. In this example, most of the status information for each interface is omitted, and an 8T-V.35 serial interface in slot 1 is used. In these examples, most of the status information for each interface is omitted, and the eight serial interfaces (0--7) are in port adapter slot 1. (Interfaces are administratively shut down until you enable them.)

Router# sh int serial 1/0
Serial1/0 is up, line protocol is up
  Hardware is M8T-V.35
  Internet address is 1.1.1.0
  MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255
  Encapsulation HDLC, loopback not set, keepalive set (10 sec)
(display text omitted]

Router# sh int serial 1/1
Serial1/1 is up, line protocol is up
  Hardware is M8T-V.35
  Internet address is 1.1.1.1
  MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255
  Encapsulation HDLC, loopback not set, keepalive set (10 sec)
(display text omitted]

Router# sh int serial 1/2
Serial1/2 is up, line protocol is up
  Hardware is M8T-V.35
  Internet address is 1.1.1.2
  MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255
  Encapsulation HDLC, loopback not set, keepalive set (10 sec)
(display text omitted]

Router# sh int serial 1/3
Serial1/3 is up, line protocol is up
  Hardware is M8T-V.35
  Internet address is 1.1.1.3
  MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255
  Encapsulation HDLC, loopback not set, keepalive set (10 sec)
(display text omitted]

Router# sh int serial 1/4
Serial1/4 is up, line protocol is up
  Hardware is M8T-V.35
  Internet address is 1.1.1.4
  MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255
  Encapsulation HDLC, loopback not set, keepalive set (10 sec)
(display text omitted]

Router# sh int serial 1/5
Serial1/5 is up, line protocol is up
  Hardware is M8T-V.35
  Internet address is 1.1.1.5
  MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255
  Encapsulation HDLC, loopback not set, keepalive set (10 sec)
(display text omitted]


Router# sh int serial 1/6
Serial1/6 is up, line protocol is up
  Hardware is M8T-V.35
  Internet address is 1.1.1.6
  MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255
  Encapsulation HDLC, loopback not set, keepalive set (10 sec)
(display text omitted]

Router# sh int serial 1/7
Serial1/7 is administratively down, line protocol is down
  Hardware is M8T-V.35
  Internet address is 1.1.1.7
  MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255
  Encapsulation HDLC, loopback not set, keepalive set (10 sec)
(display text omitted]

With the show interfaces type slot/port command, use arguments such as the interface type (serial, and so forth), slot, and port number (slot/port number) to display information about a specific serial interface only.

The following example of the show interfaces serial slot/port command shows all of the information specific to the first 8T-V.35 interface port (interface port 0) in port adapter slot 1:

Router# sh int serial 1/0
Serial1/0 is up, line protocol is up
  Hardware is M8T-V.35
  MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255
  Encapsulation HDLC, loopback not set, keepalive set (10 sec)
  Last input never, output 1d17h, output hang never
  Last clearing of "show interface" counters never
  Output queue 0/40, 0 drops; input queue 0/75, 0 drops
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     0 packets input, 0 bytes, 0 no buffer
     Received 0 broadcasts, 0 runts, 0 giants
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
     24 packets output, 5137 bytes, 0 underruns
     0 output errors, 0 collisions, 0 interface resets
     0 output buffer failures, 0 output buffers swapped out
     0 carrier transitions     DCD=down  DSR=down  DTR=down  RTS=down  CTS=down

The show version (or show hardware) command displays the configuration of the system hardware (the number of each interface processor type installed), the software version, the names and sources of configuration files, and the boot images. Following is an example of the show version command:

Router# show version

Cisco Internetwork Operating System Software
IOS (tm) 7200 Software (C7200-J-M), Version 11.1(6) [rmontino 105]
Copyright (c) 1986-1996 by cisco Systems, Inc.
Compiled Sun 04-Aug-96 06:00 by rmontino
Image text-base: 0x600088A0, data-base: 0x605A4000

ROM: System Bootstrap, Version 11.1(6) RELEASED SOFTWARE

Router uptime is 4 hours, 22 minutes
System restarted by reload
System image file is "c7200-j-mz", booted via slot0

cisco 7206 (NPE150) processor with 12288K/4096K bytes of memory.
R4700 processor, Implementation 33, Revision 1.0 (Level 2 Cache)
Last reset from power-on
Bridging software.

SuperLAT software copyright 1990 by Meridian Technology Corp.
X.25 software, Version 2.0, NET2, BFE and GOSIP compliant.
TN3270 Emulation software (copyright 1994 by TGV INC).
Chassis Interface.
4 Ethernet/IEEE 802.3 interfaces.
2 FastEthernet/IEEE 802.3 interfaces.
4 Token Ring /IEEE802.5 interfaces.
12 Serial network interfaces.
1 Compression port adapter.
125K bytes of non-volatile configuration memory.
1024K bytes of packet SRAM memory.

20480K bytes of Flash PCMCIA card at slot 0 (Sector size 128K).
8192K bytes of Flash internal SIMM (Sector size 256K).
Configuration register is 0x2

To determine which type of port adapter is installed in your system, use the show diag slot command. Specific port adapter information is displayed, as shown in the following example of an 8T-V.35 port adapter in chassis slot 1:

Router# show diag 1

Slot 1:
Mueslix serial (V.35) port adapter, 8 ports
Port adapter is analyzed
Port adapter insertion time 2d09h ago
Hardware revision 255.255               Board revision UNKNOWN
Serial number     4294967295    Part number    255-65535-255
Test history      0xFF          RMA number     255-255-255
EEPROM format version 1
EEPROM contents (hex):
0x20: 01 0D FF FF FF FF FF FF FF FF FF FF FF FF FF FF
0x30: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF

For command descriptions and examples for the Cisco 7200 series routers, refer to the publications listed in the section "If You Need More Information" on page 2.

Using the ping Command

The packet internet groper (ping) and loopback commands allow you to verify that an interface port is functioning properly and to check the path between a specific port and connected devices at various locations on the network. This section provides brief descriptions of these commands. After you verify that the router has booted successfully and is operational, you can use these commands to verify the status of interface ports. Refer to the publications listed in the section "If You Need More Information" on page 2, for detailed command descriptions and examples.

The ping command sends an echo request out to a remote device at an IP address that you specify. After sending a series of signals, the command waits a specified time for the remote device to echo the signals. Each returned signal is displayed as an exclamation point (!) on the console terminal; each signal that is not returned before the specified timeout is displayed as a period (.). A series of exclamation points (!!!!!) indicates a good connection; a series of periods (.....) or the messages [timed out] or [failed] indicate that the connection failed.

Following is an example of a successful ping command to a remote server with the address 1.1.1.10:

Router# ping 1.1.1.10 <Return>
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echoes to 1.1.1.10, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/15/64 ms
Router#

If the connection fails, verify that you have the correct IP address for the server and that the server is active (powered on), and repeat the ping command.

The loopback test allows you to detect and isolate equipment malfunctions by testing the connection between the 8T-V.35 port adapter interface and a remote device such a modem or a CSU/DSU. The loopback subcommand places an interface in loopback mode, which enables test packets that are generated from the ping command to loop through a remote device or interface cable. If the packets complete the loop, the connection is good. If not, you can isolate a fault to the remote device or interface cable in the path of the loopback test.