All PSTN lines are not working

We have connected 23 PSTN lines to FXO cards.
When i type core show channels ony 12 lines only comes active.
Its only allowing 8 outgoing and 4 incomings.

How can i solve the problem.

I hope any experianced hands can help me on this?..Please advise


You say - cards. When I had project which included PCI cards - then we read that it is not good idea to use more then 1 card per PC - it was few years ago but…

sorry for the wrong entry"cards"
we only using one card

I would check your dahdi configs, and make sure all of your contexts are correct. Then restart dahdi and asterisk/or the server.