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Powering on the LN2600 Router


The LN2600 router derives its power from a single -48 VDC power supply with dual power inputs.


The LN2600 router has more than one power source. Ensure proper care while connecting the DC power supply to the router.

You connect DC power to the router by attaching power cables from the external DC power sources to the terminal on the power supply ports. The power cables are not provided with the router.

To connect the DC source power cables to the router for each power supply:

  1. Power off the dedicated customer site circuit breakers. Ensure that the voltage across the DC power source cable leads is 0 V and that there is no chance that the cable leads might become active during installation.
  2. Attach an electrostatic discharge (ESD) grounding strap to your bare wrist, and connect the strap to one of the ESD points on the chassis.
  3. Verify that the DC power cables are correctly labeled before making connections to the power supply. In a typical power distribution scheme where the return is connected to chassis ground at the battery plant, you can use a multimeter to verify the resistance of the 48V and RTN cables to chassis ground:
    • The cable with very large resistance (indicating an open circuit) to chassis ground is –48V.

    • The cable with very low resistance (indicating a closed circuit) to chassis ground is RTN.

  4. Loosen the screws from the power terminals using a 2.5 mm slotted screw driver.
    Figure 1: Dual DC Power Source
    Dual DC Power Source

    You must ensure that power connections maintain the proper polarity. The power source cables might be labeled (+) and (–) to indicate their polarity. There is no standard color coding for DC power cables. The color coding used by the external DC power source at your site determines the color coding for the leads on the power cables that attach to the terminal studs on each power supply.

  5. Insert the power cables as specified to the respective power terminals, and secure the cables with the screws.
    • Secure the positive (+) DC source power cable to the RTN (return) terminal.

    • Secure the negative (–) DC source power cable to the –48V (input) terminal.


    Ensure that each power cable seats flush against the surface of the terminal block as you are tightening the screws. Ensure that each screw is properly threaded into the terminal. Applying installation torque to the screw when improperly threaded may result in damage to the terminal.

  6. Repeat Step 4 through Step 5 for the remaining power supply.
  7. Arrange the other end of the power cables in a single bundle, and pass them through the power cable entrance (see LN2600 Router Cable Management System).
  8. Power on the dedicated customer site circuit breakers.
  9. Monitor router startup on the console and the LED on the front panel of the LN2600 router to verify that the router is booting properly. For information on the LN2600 router status LED, see LN2600 Router Status LED.

As a standard part of the boot process, the router runs startup power-on self test (SPOST) and then power-on self test (POST) diagnostics.

A successful startup looks similar to the following example:

For normal operation, allow the autoboot to proceed. Do not press any key when you get the Hit any key to stop autoboot: message.

Full POST diagnostics then run, and the system starts Junos OS normally. If detailed diagnostics must be run, or if alternate media (for example, a USB storage device) must be booted, press any key before or during the 1-second countdown. The following bootstrap prompt is displayed:

If POST diagnostics or the bootstrap sequence fails, the bootstrap prompt is displayed again, and the front panel LED lights turn red.