Are trunks and stations interchangeable in TDM cards?

Hi all,

I’m trying to find the right Digium card for my first Asterisk system.
I would like to connect 3 extensions (good old analog phones) and the PSTN to a PC running Asterisk.

I am aiming at a TDM410 card, in particular the Digium TDM431B - 1 FXO 3 FXS PCI Card.

On the web site of a Digium distributor in the UK I read:
“The trunk and station modules are interchangeable, allowing the creation of any combination of interfaces.”

What does that mean? I thought this card had exactly 1 FXO + 3 FXS.

Thanks in advance,



The Digium TDM cards use small daughter boards that are either FXO or FXS the TDM 400 uses 4 of these and any type can connect to any position.