Now, regarding to the PRI configurations: The provider is using: ISDN PRI E1, hdb3 and they disable the CRC4 At the /etc/dahdi/system.conf I added the following: span=1,1,0,ccs,hdb3,yellow bchan=1-15,17-31 dchan=16 I have a question, as I am using E1 so it is a wrong to use a loadzone us? Because us is using T1 and not E1? At the /etc/asterisk/chan_dahdi.conf I added the following: context=Incoming group=0 signaling=pri_net (and really I do not know if I have to use pri_cpe) switchtype=euroisdn channel=>1-15,17-31 Well, Do I miss any thing? What commands that can help me to know if I have hardware failure in the card, if the E1 is UP or not? Your kindly help is highly appreciated. Regards Bilal