Hi, in case this is still an active topic? (not 100% clear, is >1 mo later now).
For what it is worth. My usual simple FAX setup is
- get the FAX did ported to VoipMS / or if you are not confident, first purchase such a FAX DID and do some testing to pre-validate all that I say here.
- use preferred POP / they have many in USA-Canada and support DID in ~most parts of the world, good coverage in USA/Canada for sure.
- after that, I just don't even bother with 3cx getting involved in the FAX stuff. I get the feeling 3cx prefer people to not use 3cx for faxing more-or-less. For that matter I prefer if my clients don't get involved in faxing either (whoo! modern 1990's tech! wow, I can send it as if by courier, and it gets there NOW instead of same-day-later. so much cheaper than same-day courier as well. Sigh. yes, I know some workflow depend on fax, maybe we get rid of fax machines before the Y3K ? we shall see.)
anyhow. enough semi-rude tongue-in-cheek.
next then:
VoipMS have a nice simple web-admin portal, you may go here and setup
(a) FAX_TO_EMAIL config > so this routes inbound faxes to what destination email address you designate
and then
(b) EMAIL_TO_FAX config -> allows your team in the office to easily route outbound faxes via email, ie, "Here is a PDF, drag and drop to outlook, send it to the gateway address email recipient at voip.ms . and designate the FAX recipient as part of subject line of message / as per the hints doc at voip.MS
(c) IF you are feeling like more fun, and want to support legacy FAX machine or MFP>FAX outbound over analog line, then find yourself an ATA you don't hate, configure it as a SIP Client against a SIP sub account on VoipMS and then allow the legacy physical fax scan machine to squeeze the faxes out via analog > ATA > Landline > VoipMS is your carrier > terminates the call to the external FAX ## and you send the physical paper fax out this way. Ugh, so much fun but it generally works. I've setup various Sipura, Cisco, Handytone over the years in this sort of config, generally 'it just works' unless someone kicks the power plug for the ATA or something like that.
clearly the email-to-fax and fax-to-email are a bit cleaner IMHO but some workflows still depend on physical paper I realize (sigh)
Tim