My employer has a Siemens PABX system which was installed about 5 years ago (before I arrived). There are 3 ISDN wall boxes which are labelled as follows:

• ISDN 2e (CH1/2)
• NTE8 (CH3/4)
• ISDN 2e (CH5/6)

The green LEDs on the CH3/4 and CH5/6 boxes are on but the CH1/2 LED flashes constantly and I'm trying to find out if this is indicating a fault on our system.

BT ran a remote line test and say there is no fault showing, but will charge us if they come out and there is a fault with our equipment. I called the people who maintain our exchange and they think it's BT's problem.

Does anyone know what the flashing green LED means? Is it a fault condition, and if so is it our equipment or BT's?

Thanks in advance,

Mike

Hi, and thanks for the helpful reply. I swapped the plug as you suggested and the flashing light did indeed follow the line. I will get the people who maintain our system to come out and have a look at the PBX.

My colleagues here tell me that the light has been flashing for many months, but I'm not aware that we've been missing any calls.

Mike

Line cards generally come with two ports each, so you likely had 4 ports available, and are only using 3.  They have got you to swap the port over, and then re-programmed the equipped lines, possibly remotely.