On Thu, 2 Dec 2010, Kevin P. Fleming wrote: > On 12/02/2010 10:58 AM, Jeff LaCoursiere wrote: > >> I would love to see a DSP "modem" that could answer an asterisk channel, >> send the data stream over TCP to some remote asterisk, which could then >> "relay" the stream by making an outbound DSP modem call on a PSTN trunk. >> Has anyone attempted anything like this? > > Guess what? There is already a standard for this, called V.150, Modem > over IP. It certainly would be possible to implement this sort of thing > for Asterisk, and some small steps in that direction have been taken way > in the past... I'd suggest doing some Google searching to see what you > can find.
I did find an interesting thread for this in 2006 :) I wonder if it is being made overly complicated, though. I guess what I was envisioning is something like IAXModem that would provide a serial device... if that could be done, to the point where minicom or similar could actually make data calls via a PSTN line, then I would be very close to what I need. I envision this: An ATA on the local LAN with a dockstar running asterisk. An instance on this machine of an "iaxmodem-like" DSP that registers as an IAX extension and can be called by the ATA. A "serial proxy" daemon on that same machine that has the tty device open and sees the inbound call, answers it, then constructs a TCP session to the "serial proxy" daemon on the remote asterisk server. On the remote asterisk server another instance of an "iaxmodem-like" DSP accepts the Hayes commands to dial out again to the alarm company's modem pool, and once connected starts feeding it the data stream coming from the alarm panel at the client's site, and sends back the replies in the same manner. I really think this would work, and the daemon wouldn't be that difficult to write. I don't think I have a prayer of hacking iaxmodem to do what is needed to emulate a modem though :) Between the dockstar and the ATA (which I am already providing for dialtone anyway) it is around a $40 cost solution for me, and the customer gets to drop the POTS line, which is around a $30/month savings for them. I'd probably just eat the added cost to get the customer, and could even charge some modest fee for the "alarm connection" that would still in the end save them money. > >> So hoping this will spark some comments on the concept in general, and >> really hoping someone has actually tackled something similar. It could >> open up a nice niche for even residential customers with expensive POTS >> lines dedicated to alarm systems. > > Or those customers could switch to cell-connected alarm panels (which > are rapidly becoming less expensive and provide reliability benefits), > or even IP-connected alarm panels. Either choice would be better in the > long term than trying to convince an ancient alarm panel's modem to work > over a packet network. Totally agreed - but in our remote area of the world ancient technology will continue to be used for some time to come, and I need a way to sell service to those people that will refuse to replace any of their equipment. I don't think I am alone here... and the concept would also apply to credit card processing machines, ATM machines, and other embedded modem devices that will probaby be with us for some time. Look at fax, for example. Wouldn't we love to tell our customers to dump their old fax machines for scanners and email? Some people just won't until the thing catches fire or otherwise dies. So is there anyone out there with the DSP skills to do the "iaxmodem-like" part of what I describe above? Would a bounty raise any interest? A little more searching today turned up this: http://www.gouloum.fr/code/sm/sm.html Which is REALLY close to what I need... Cheers, -- Jeff LaCoursiere SunFone -- _____________________________________________________________________ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- New to Asterisk? Join us for a live introductory webinar every Thurs: http://www.asterisk.org/hello asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
