Call Answered

I am trying to make a call out from my VoIP Client to the LAND line using a DIGIUM TDM 400P card. When i attempt a call, the following is displayed in my asterisk window: Zap/4-1 answered SIP/200-683c

It says call is answered but, we receive no call. How can we verify whether the card is working ? i did a ZAP show status, and it looks
fine.

When we try to make calls between two VoIP clients, we have no issues,
but when we make calls between IP and LAND line, thats when the problem arises.

Please guide me.

Thank You,

Ganesh