Table Of Contents

Troubleshooting the Cisco 2524 and Cisco 2525 Routers

Running Diagnostic Tests

Getting Help

Troubleshooting the Cisco 2524 and Cisco 2525 Routers

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This appendix describes how to troubleshoot the Cisco 2524 and Cisco 2525 routers by referring to the LEDs on the rear panel of the chassis (see and ) and on the network processor modules (see through ).

The LEDs indicate the current operating condition of your router. You can observe the LEDs, note any fault condition that the router is encountering, and then contact your system administrator or a customer service representative, if necessary. describes the LEDs on the router chassis and WAN modules.

Table B-1 LEDs

Chassis/Module	LED	State	Description
Router chassis	Power	On steadily	Power is being supplied to the router.
		Off	Power is not reaching the router. Verify that the power supply is plugged into the wall receptacle, and that the cable from the power supply to the router is connected.
	Activity (Ethernet/ Token Ring1 )	Flickering	The Ethernet/Token Ring LAN connection is transmitting and receiving data normally.
		Off	The Ethernet/Token Ring LAN connection is not transmitting or receiving data. Check the Ethernet/Token Ring cable connection.
Router chassis	Ethernet link (Cisco 2524)2	On	The router senses the Ethernet 10BaseT link integrity signal, indicating normal operation.
		Off	The router is not sensing the Ethernet 10BaseT link integrity signal. Check the Ethernet 10BaseT cable connection.
	In-ring (Cisco 2525)	On	The router has been successfully inserted into the Token Ring, indicating normal operation.
		Off	The router has not been successfully inserted into the Token Ring. Check the Token Ring cable connection.
2-wire switched 56-kbps, 4-wire 56/64-kbps, and factional T1/T1 WAN DSU/CSU modules	RX	On	Data is being received at the DTE interface.
	TX	On	Data is transmitting from the DTE interface.
	CD (Carrier)	On	The DSU/CSU in the module is communicating with another DSU/CSU.
	Loopback	On	The DSU/CSU is in loopback mode.
	Alarm	On	An alarm condition is present.
Serial module	Activity (serial activity)	Flickering	The serial WAN connection is transmitting and receiving data normally.
		Off	The serial WAN connection is not transmitting or receiving data. Check the serial cable connection.
ISDN BRI module	Activity (ISDN BRI activity)	Flickering	The ISDN BRI WAN connection is transmitting and receiving data normally.
		Off	The ISDN BRI WAN connection is not transmitting or receiving data. Check the BRI cable connection.
ISDN BRI with integrated NT1 module	ACT (ISDN BRI activity)	Flickering	The ISDN BRI (with integrated NT1) WAN connection is transmitting and receiving data normally.
	NT1	On	The router detects the ISDN link integrity signal at the U interface3 and the internal S/T interface4 , indicating that an ISDN connection has been established.
ISDN BRI with integrated NT1 module		Blinking once per second	The ISDN connection at the U interface is up, and the internal S/T interface is coming up. If this state persists, the ISDN port is either not configured or it is configured incorrectly.
		Blinking eight times per second	The ISDN connection at the U interface is coming up.
		Off	The router is not detecting the ISDN link integrity signal. An ISDN connection has not been established. Check the BRI cable connection.

1 The Token Ring activity LED is labelled ACT. 2 The Ethernet link LED is for the Ethernet 10BaseT port only; it does not work with the Ethernet AUI port. 3 The U interface is from the wall jack (telco interface) to the NT1 device. 4 The S/T interface is from the ISDN port on the module to the microprocessor.

Running Diagnostic Tests

If you have the fractional T1/T1 module, you can use external test equipment with the monitor jack labeled OUT to monitor signals coming into the RJ-48C port, without interrupting normal data transmission. You can use the monitor jack labeled IN to inject data, which would interrupt normal data transmission.

Getting Help

For information on technical support, onsite service, and exchange and repair services, refer to the Cisco Information Packet publication that shipped with your router.