hi. in my office we do have an isdn line with three numbers. one of the numbers it serves as fax. the ISDN in in a fritzbox 7170. each number is assigned in one of the analogue ports. everything works fine up to now.
i do need UC functionallities and i have installed a raspberry pi with asterisk. each of the numbers is assigned to one of the ip extensions 620-621. then i got all fritzbox's IP extensions registered to asterisk. regarding voice everything works fine. the problem is for fax. i have installed iaxmodem and hylafax to manage the faxes. unfortunattely there is no way to send/receive faxes. i thought that it might be the installation and i have tried an internet sip trunk that offers g711 codec and the faxing does works.
unifortunatelly there is no way to make it work in fritzbox/hylafax/iaxmodem.
anyone that might be able to help?