Troubleshooting Cisco 700 Series Routers

LED Functions

This section describes the functions of the Cisco 700 series routers' LEDs.

Front Panel LEDs

The front panel LEDs display the activity status of the router as connections are made and as packets are sent and received.

Table 8-2 lists the LEDs and their functions.

Table 8-2 : Front Panel LED Functions

LED	Function
RDY (Cisco 750 Series)RD (Cisco 760 Series)	Indicates the router's operating status. Lights when power is supplied to the router and when the router completes its self-test procedure and begins operating.
NT1 (Cisco 752, Cisco 753, Cisco 762 and Cisco 766 only)	Lit (unblinking) indicates that the internal NT1 and the ISDN switch have synchronized over the ISDN line. Blinking (5 blinks per second) indicates that the internal NT1 is attempting to synchronize with the telephone switch. Blinking (1 blink per second) indicates that the internal NT-1 is attempting to synchronize with the ISDN terminal devices.
LINE	Lit (unblinking) indicates synchronization between the NT-1 S interface and the ISDN terminal device(s). Also indicates framing between the router and the ISDN switch.
LAN	Lights when packets are sent to or received from the Ethernet within the last minute.
LAN RXD	Blinks when packets are received from the Ethernet.
LAN TXD	Blinks when packets are sent to the Ethernet.
CH1	Blinks when a call is being connected on the first ISDN B channel. After the call is established, the LED remains lit without blinking.
CH1 RXD	Blinks when packets are received from the first ISDN B channel.
CH1 TXD	Blinks when packets are sent on the first ISDN B channel.
CH2	Blinks when a call is being connected on the second ISDN B channel. After the call is established, the LED remains lit without blinking.
CH2 RXD	Blinks when packets are received from the second ISDN B channel.
CH2 TXD	Blinks when packets are sent on the second ISDN B channel.
PHONE(Cisco 753 only)	Blinks when the basic telephone service line is off-hook. Blinks in one of the following patterns when entering DTMF1 commands: On and off twice per second for 2 seconds if the command is entered correctly. On and off once per second for 4 seconds if the command is entered incorrectly.
PH 1PH 2(Cisco 765 and Cisco 766 only)	Blinks when the corresponding basic telephone service line is off-hook. Blinks in the following patterns when entering DTMF commands for the corresponding basic telephone service port on the router: Blinks on and off twice per second for 2 seconds if the command is entered correctly. Blinks on and off once per second for 4 seconds if the command is entered incorrectly.

¹ DTMF = dual-tone multifrequency.

Rear Panel LED

There is one LED on the router's rear panel: the LINK LED. The LINK LED remains lit when the router is configured to function as an Ethernet hub or when the router is connected to an Ethernet hub.

LED Diagnostics

The front panel LEDs can be used for diagnostic purposes. When the router is powered on, it performs a series of self-tests. After these tests are completed, any operational problem is represented by a combination of lit and unlit LEDs.

Table 8-3 lists the combinations of lit and unlit LEDs and their significance.

Table 8-3 : LED Error Messages

RDY	NT1	LINE	CH1	CH2	Test Result
On	Blinking several times per second	See Note1			Internal NT1 is unable to synchronize with the ISDN switch
On	Blinking one time per second				Internal NT1 is synchronized with the ISDN switch, but is unable to synchronize with the ISDN terminal devices
		On			Waiting for software
On		On	On	On	Processor inactive
					Processor self-test error
				On	EPROM2 checksum error
			On		RAM3 error
			On	On	Flash memory error
		On		On	HDLC4 packet chip error
		On	On		Configuration port error
		On	On	On	ISDN interface chip error

¹ Note: A blank cell indicates that the LED is not lit.
² EPROM = erasable programmable read-only memory.
³ RAM = random access memory.
⁴ HDLC = High-Level Data Link Control.

Configuration Problems

The following conditions are often caused by router configuration problems:

• Router Calls Itself
  

• Terminal Identifier or SPID Problems
  

• Outgoing Calls Cannot Be Made
  

• Outgoing Call Is Rejected
  

• 10BaseT Connectivity Problems
  

Router Calls Itself

If the router calls itself, check that the number configured with the set number command is not the same number configured with the set directory number command.

ISDN supports two separate logical data channels on the same physical line. If these two numbers are the same, the router might attempt to call itself when on-demand dialing is enabled or if the user issues the call command.

Terminal Identifier or SPID Problems

Either of the following two messages received on your terminal might indicate a SPID configuration problem:

Channel Not Available        
Facility Not Subscribed

• The wrong ISDN switch type was set with the set switch command.
  

• The ISDN line was incorrectly configured by the ISDN service provider. Confirm the line configuration with the ISDN service provider.
  

• The SPIDs were not entered or were entered incorrectly with the set spid command.
  

Outgoing Calls Cannot Be Made

If outgoing calls are unsuccessful, check the following conditions:

• A telephone number was not correctly configured with the set number command.
  

• The SPIDs were not entered or were entered incorrectly with the set spid command.
  

• The ISDN B channel is under operator control and does not respond to the router. Contact the ISDN service provider.
  

Outgoing Call Is Rejected

If an outgoing call is initially successful and then rejected, check for the following conditions:

• A telephone number was incorrectly configured with the set number command.
  

• The number called is busy. Try the call again.
  

• The ISDN line was incorrectly configured by the ISDN service provider. Confirm the line configuration with the ISDN service provider.
  

• If using authentication, the router's client password or secret might not match the remote router's host password or secret.
  

10BaseT Connectivity Problems

If you have problems connecting to the 10BaseT Ethernet network, check the node/hub configuration. On the Cisco 750 series routers, this configuration is set by moving a set of five jumpers inside the chassis. On the Cisco 760 series routers, this configuration is set with a switch labeled HUB/NODE on the rear panel. For more information, refer to the appendix "Configuring Cisco 750 Series Routers to Operate as an Ethernet Hub."

Software Loading Errors

Software load errors can occur when downloading new software. If an error occurs during a software download, a combination of blinking LEDs will indicate the problem. An error code will also be displayed on the terminal.

Table 8-4 lists the combination of blinking LEDs that indicate an error, along with the error code and a description of the error.

Table 8-4 : LED Error Messages---Software Download

Blinking LED	Error Code	Description of Error
Line CH 2	E-1	A framing, parity, or overflow error occurred during software download, usually because of an incorrect data rate or configuration port setting. Check the data rate and configuration port settings.
CH 1	E-2	A colon did not occur at the beginning of a line in the new software image file. Either the software image file is corrupted, or some characters were entered before the download started. Start the software load process again. If the same error occurs, contact Cisco for a new software image file.
Line CH 1	E-3	One line in the software image file has a bad checksum, usually because of a temporary line error. Start the software download process again.
Line CH 1 CH 2	E-5	The software image file has a bad or missing checksum. Start the software load process again. If the same error occurs, contact Cisco for a new software image file.

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