TDM400 (TDM04B). When should ligh LED on this card?

I have 4-FXO ports TDM04B card. Curently all 4 LEDs are lighting after Linux (Debian krn_2.6.15) botted up. Is it normal conditions or not? I thought LED should light if phone line is switched in to that particular port. Now I have situation that LEDs lighing on in any condition (phone line pluged in or pluged out). Can anyone share your experience?

I believe that the lights come on for the ports with modules installed as soon as the drivers are loaded.

I’ve finde out: LED on TDM400 mother board are lighting if FXO/FXS mudules are sucsessfuly attached to motherboard of TDM400 and have connection. I’m agree with you, in case if Zaptel drivers are not installed LEDs not lighting.