[AccessD] FoIP vs. Inter(net)Fax custom solutions

Hi All --

I'm looking for the most cost effective international faxing solution
(sending fax messages) controlled by custom coding - there are many AFAIHF
but if generalize them then "just" two options are looking worth to be taken
into consideration (?), namely:

- (1) Internet Fax Service Provider, e.g

http://www.interfax.net/en/lp3/uk-fax-over-ip (description)
http://www.interfax.net/en/prices (costs)
http://www.interfax.net/en/dev API)
http://faxing-service-review.toptenreviews.com/ (top 10 fax service
providers review)

and

- (2) Fax over IP (FoIP) "boardless" (virtual) Server Solution:

http://www.biscom.com/products/fax-servers/fax-over-ip.htm (FoIP in general)
http://www.biscom.com/downloads/Fax_server_virtualization.pdf (FoIP
virtualization)
http://www.ifax.com/shop/brooktrout-sr140-2f.html (FoIP software)
http://www.biscom.com/products/fax-integrations/sdk-api.htm (API)
http://voip-service-review.toptenreviews.com/ (top 10 VoIP providers)

The former is looking simple and quick to start with but the costs per a fax
page sent are rather high.
The latter is looking rather complicated and a bit pricey to start with but
it could provide significant costs cuts in long run I guess?
Do you have any experience with using the second option?
I think I don't understand in details how it works - would it be correct to
write that it works this way:

- a) custom code via API submits a fax message source (plain text or MS Word
doc or .pdf doc ...) to a "boardless" fax server software (e.g. BrookTrout
SR140 referred above),
 
- b) the "boardless" fax server software makes conversion of the source docs
to the fax message image to be sent via local (?) VoIP provider's hardware
(which SR140 communicates with via IP) to the specified (international) fax
number. (The destination fax device could be an old (T.30) fax machine
connected to the PSTN lines),

- c) (local) VoIP provider's hardware communicates with destination
(international) VoIP provider's hardware via Internet IP gateways, 

- d) destination (international) VoIP provider's hardware via VoIP-to-PSTN
gateway communicates with destination fax machine...

The costs cuts in the long run (I guess) would be the result of lower costs
of the local VoIP/FoIP services (with international faxing option included)
per a fax page sent comparing with Internet Fax Services costs per a fax
page sent...

I can be completely wrong with my guessing about second (FoIP fax server)
option - could you please advise/share your experience in that area? (The
second option could also provide real-time reliable FoIP fax message
transmittion?)

Thank you.

--
Shamil