File tranfer

[fotis_rez]

We are a small business, with three branches at different cities, and one central office.
we want to create a lan (or some-kind) that will enable us to transfer files with each other. Each branch store has a H/Y with an FXO card and asterisk installed, and the central office has a H/Y with 8-port FXO/FXS card and asterisk installed. the telephone lines of the branches are analog lines (POTS).
my question is if there is a product, free or retail, that we can use so that we can access our branches, and transfer files, with the existing equipment (H/Y, ubuntu, FXO + FXS cards, analog lines)

[dalenoll]

Do your sites have Internet Access?

If yes, there are several ways to connect the sites together for file transfer and possibly even calling without the telephone charges. You could create a VPN. Perhaps with your existing routers or you can use openVPN. Then you can use standard file transfer protocols such as ftp to transfer files around. If your Internet bandwidth is sufficient, you can create SIP or IAX2 trunks between your Asterisk servers and configure the dialplan to send calls over the VPN to the appropriate site. With a little more work, you can create dialplan that will route a call from one location through another location and out the analog trunk and reduce or avoid long distance charges.

If not, then you you can always get some modems and travel back to the pre-broadband Internet days and build a uucp network.

Forgive me for being a bit thick today, but what do you mean by 'H/Y'?

[fotis_rez]

we do not have internet access at our branches as they are in areas with no broadband connections,
by H/Y i mean computers, they are running ubuntu 11.10 and have asterisk installed,
if you could please be more specific on what we could try,
if there is a software we could buy?

[dalenoll]

Well, back in the days before broadband, uucp (Unix to Unix Copy Program) was a method if networking over telephone lines. This was not an 'always on' connection, it was more of a as needed connection and one system would contact another to transfer files then hang up when finished. I have not thought about it in over 20 years, but the package appears to still be available.

I think that Cisco also has an 'Async' module for their routers. I do not know much about them or about how it would be setup.

[david55]

I don't think this is the right forum.

The difficulty is getting software to act as modems. Nowadays, there is no mainstream market for that.

I would point out that internet connectivity doesn't require broadband, and if you are in a country which has areas to which broadband doesn't reach, your ISPs really ought to still support analogue modems. I'd therefore suggest that the easiest option is to have one line bypass Asterisk and go direct to a real hardware analogue modem. My feeling is that anything else, although the software may exist, will require you to hire someone with quite deep technical skills, as they will be dealing with technology that is no longer fashionable, at a quite deep level.

Also, if you are somewhere with no broadband, it is quite possible that the analogue telephone network will only support quite slow modems.

You will not be able to attain more than 33.6kbps point to point, for pre-compressed data, even if the network is good. You might be able to achieve 56kbps downlink from an ISP, but you would have to use a hardware modem directly on the incoming line, or implement the modem entirely in software, if going through Asterisk (or any digital PABX). This would also depend on your local PSTN exchange being digital and being connected to the rest of the country, digitally.

[david55]

Googling "sip software modem" might find you the sort of software you need for a software solution. I haven't checked out any of the hits, although the summaries suggest a lot of these are people failing to find anything useful.