We have the following VoIP setup:
codec = G.711
fax protocol = modem passthrough
voice and fax are working fine in both directions between Site1 and Site2.
voice and fax are working fine in both directions between site2 and site3
Voice between Site1 and Site3 is working fine in both directions.
FAX is working fine from Site3 to Site1.
However FAX is not working fine from Site1 to site3..In deed, if we need to send more than 1 page fax, only the first page is printed/received and not all the pages.
Thanks for your quick feedback as this solution is up and running.