Hi Mary Christmas to y'all ! I am trying to configure * with one TDM and one ISDN and Bri-stuff, all is ok with only TDM but when add ISDN I get following error: I have tried to switch fxs/fxo but then I get error also without ISDN, card is configured from Digium with FXS(green) modules are closest to the bracket. ZT_CHANCONFIG failed on channel 1: Invalid argument (22) Did you forget that FXS interfaces are configured with FXO signalling and that FXO interfaces use FXS signalling? loadzone=no defaultzone=no fxoks=1-2 # Make sure that the FXS(green) modules are closest to the bracket fxsks=3-4 # This is for the FXO module(s) because it uses FXS span=2,1,3,ccs,ami bchan=5-6 # Old value: 1-2 dchan=7 # Old value: 3 Thank you ! HB Norway