PRI card - What to check if LED Lay 1 and/or 2 on PRI card do not light up/blink

There is a problem in the communication on the ISDN PRI line. To fix the problem check following please:

  1. Check if you are using straight or crossover cable (you should use the straight one).
  2. Check if jumpers on the PRI board are set correctly for the NT/TE mode (JP2 and JP3, see the picture below, you can also find more details in the manual).
  3. Check the Master/Slave settings in the ISDN parameters menu.
  4. Check settings of CRC of Layer 1 on PRI interface (see the section Gateway configuration>ISDN parameters: CRC in the PRI config tool).