1.5 Assembling and Cabling WAN Components
1.5.8 Verifying telecommuter-site installation
Each telecommuter site router has LED displays that allow you to verify that the router components are installed and functioning properly. On the Cisco 766 router, you can use the LEDs on the front of the router to determine router performance and operation, as shown in the Figure.

The Cisco 700 series LEDs and their descriptions are as follows:

  • RD -- The ready LED indicates the router operating status. This LED is on when power is supplied to the router, the router passes the self-test, and it is operating normally.
  • NT1 -- On Cisco 700 series routers that have an internal NT1, the on LED indicates that the NT1 and ISDN switch have synchronized over the ISDN line. When blinking five blinks per second, the internal NT1 is attempting to synchronize with the telephone switch. When blinking one blink per second, the internal NT1 is attempting to synchronize with the ISDN terminal devices.
  • LINE -- An online LED indicates synchronization between the NT1 S interface and the ISDN terminal device(s). It also indicates framing between the router and the ISDN switch.
  • LAN -- An on LAN LED indicates that frames have been sent to or received from the Ethernet within the last minute.
  • LAN RXD -- The receive LAN LED blinks when frames are received from the Ethernet.
  • LAN TXD -- The transmit LAN LED blinks when frames are sent to the Ethernet.
  • CH1 -- The channel 1 LED blinks when a call is connected on the first ISDN B channel. After the call is established, the LED remains on.
  • CH1 RXD --The channel 1 received LED blinks when packets are received from the first ISDN B channel.
  • CH1 TXD -- The channel 1 transmitted LED blinks when packets are sent on the first ISDN B channel.
  • CH2 -- The channel 2 LED blinks when a call is connected on the second ISDN B channel. After the call is established, the LED remains on.
  • CH2 RXD -- The channel 2 received LED blinks when packets are received from the second ISDN B channel.
  • CH2 TXD -- The channel 2 transmitted LED blinks when packets are sent on the second ISDN B channel.
  • PH1, PH2 -- Plain old telephone service (POTS) ports are on when a telephone, fax, or modem is in use.

There is also one LED on the rear panel, the LINK LED, which remains lit when the router is configured as an Ethernet hub, connected to an Ethernet hub, or configured as a node, and a valid physical connection to another Ethernet device is established. For a Cisco 766, the ready LED indicates the router is on and has passed its self-tests.