A friend of mine, who could not get a DSL connections because back then he lived in an uncovered area, could at least get a telephone "flat rate" for free telephone calls on Sundays.
So, he dialed in my Pentium 133 server and used my DSL connection behind a NAT every Sunday.
So I built a dial-up pool on an internal number (this place had its own PBX with ~500 phone lines) hooked to a Debian box, served by a bunch of USR Courier modems. Good times :)
I have a lot of old hardware that i want to connect to the to my network. Most of them have a 56k modem the rest a 14/28k modem. What can i use to bring them all online at the same time. I tough to use some voip adapter (from pots to ethernet) but from what i understand there are not good for modem/fax style signal, also i need something that can handle at least 8 client at the same time (the number of computer to connect is 22 at the time but i don't know how realistic is to connect all of them at the same time using this method).
When i searched (i couple of month ago, so i might get wrong some terminology) i only found some enterprise pbx that were awfully expensive (1000$) i hope for something more cheap. I didn't find anything that work.
EDIT: Also i'm not sure how to understand if the hardware that i plan to use can do what i need. What do i need to look in a pots to voip converter to work as modem "server".
If i sound confused is because i am.
I have a plan B, that consist of using serial port and emulate old style Hayes modem by a central more powerful (and modern) computer using a lot of usb2serial adapter, but i would rather avoid that since some computer have only 1 serial port and is already used for other hardware forcing me to choose between connectivity and the other device. Also some of the hardware it's not compatible with serial modem.
I've already test this approach and (expect the aforementioned shortcoming) it works quite well.
Thank you all in advance
Take a look on ebay for "terminal server", "console server", etc.
1- They seem to all use RJ45 i'd imagine that i would use a cable RJ45<->RS232. I found some on amazon, but i don't know if they are standard or i need to look for some specific type of cable.
2- Do they allow the "master" ethernet port to talk to all serial port at the same time? I found some conflitting information about it. If not the usb<->rs232 seem a better solution.
Thank you a lot!
2) The ethernet port can communicate with all serial ports. Depending on the model, you can program the serial port for PPP, SLIP, telnet, SSH, etc. Back in the old dialup ISP days, we connected modems to these terminal servers and users could either telnet to a host, or initiate a PPP session.
And yes, you can basically build your own terminal server with a bunch of those USB<->RS232 adapters.
Your best bet would probably be getting a terminal server style multiport serial card and just do PPP over serial from the client devices. The modem is an extra layer you typically don't need at all for local connections. You can get relatively inexpensive 16+ port cards and I'd expect them to be far more reliable and manageable than a wad of usb dongles.
Also some software expect to talk to a modem and don't play well with raw serial.
I searched for multi serial port card, but i had trouble finding one. Maybe i'm using the wrong keyword but i only found pci/pcie card with up to 4 serial port.
Usb seem to work decently but i admit that sometime the os (linux) seem to become confused and some serial port change name, causing some trouble. Having one card (or two) will make everything easier. I'm also considering "console server" as others have suggested.
As an alternative, PPP gives you a routed TCP/IP connection over a serial line...you offload routing onto the network layer and you can potentially have _all_ your client machines communicate with each other or even externally via standard TCP networking, and don't deal with circuit-switching the serial connections at all. For things that are TCP capable this is probably the cleanest solution.
If you want to support software that requires direct serial/modem links and not TCP, you will need something else in the mix. On the software side, I'd check the software to make sure you can't just turn off the AT commands altogether and use raw serial. Even where it wasn't a supported/intended setup, most software that explicitly handled modems allowed specifying alternate AT command strings, so you _might_ be able to just blank them out and go straight to serial. As far as circuit-switching...I know I've seen hardware devices that did this, but not in decades, so likely not easy to find any more. A quick google only turned up a bunch of datasheets for chips that could do it, but seems like you'd have to build your own device or track down a vintage device.
For multiport cards, an amazon search turned this up as the first result: https://www.amazon.com/Port-Rs232-Multiport-Serial-Card/dp/B...
So i, basically, do both. packet and circuit network according to need.
As far as circuit-switching...I know I've seen hardware devices that did this, but not in decades, so likely not easy to find any more
software based circuit switching seem to work fine for what i need, is really not that complicated, it also make me do cool thing like wiresharking!
For those systems without a serial port, for whatever reason, you can find a matching modem. If you get external serial modems, you'll be able to hook it to your multiport card, but USB modems will work too (as long as they're hardware modems). You might need to apply a DC voltage to your line to convince the modems it's working, but you probably don't need a dialtone, most modems will be fine with blind dialing. Caveat: you won't be able to get 56k without a lot of work.
If you really want, you should be able to make a back to back ATA adapters work, make sure your network isn't congested, and use PCM codec and it should work ok, but probably not great.
i looked into using serial modem, but it seemed quite complicated, and very fragile. I didn't find a lot of guide to connecting directly two modem. I tried doing some experiment with a couple of modem i had laying around but without success. Pots and modem aren't really something a know a lot of, (that's the reason of the plan B, a lot simpler and something i understand)
I also look into ATA to modem and i will probably use that for the device i cannot connect via serial, but it seem that a lot of them don't support the pcm codec (or at least i didn't found info about it), i never used one so my knowledge about them is limited, but the article should help me. also they will stay in a dedicated network so congestion shouldn't be a problem.
Many modems (notably Dreamcast modems) require line voltage to work. A normal POTS line provides a good amount of DC voltage when the line is off hook for various reasons, and a modem may use that for powering parts of itself or as a check to confirm it's properly connected. Something like this could help supply that voltage for picky modems http://dreamcast.onlineconsoles.com/phpBB2/guides_pcdcwin98....
Many modems will also default to waiting for a dial tone before dialing, but that should be configurable via the dialstring.
As with all things Telco, the terminology is strange. You're looking for the g.711 codec. It's basically what was used for T1s, so it's just right to fit a modem, because actually most ISPs were receiving calls via T1 --- that's how 56k works.
I'd expect you to get them for nearly $0 as long as you dismantle and move them yourself. Be prepared to bring a good sized truck.
Some things never change
"Plug in play! Fuck plug n play! My ass is plug n play!"
Dial in. Search for instructions. Print them out. Reboot into Linux. Try it. Doesn’t work. Write down error. Reboot into Windows. Dial up again. Search for error. Repeat until you hate yourself.
Wait, you need a new package. Go back to Windows and download it. Stick it somewhere Linux can see it. Reboot into Linux. Install the package. Find out it has missing dependencies. Go back to step one.
Got all the dependencies. Start at the top again.
I don’t remember if I ever got PPP working before I had Ethernet based net access and no longer needed dial up.
I think it could be workable if you were to set uBlock to block all images and scripts.
Ask one of the 151,287,292 people in the United States who have a landline.
Modems and fax machines are pretty sensitive, and pushing that sound over a packet switched network with UDP instead of a circuit switched network leaves a lot to be desired.
So there are some places that still support old copper lines, but in many places, if they have to run a new line, they'll run a coax or fiber to your house and give you a plug in off of that.
It's basically not an offering in many places now.
By the time you've got a dedicated channel for the fax machine (missing an inbound PO delivered via fax because the sales team is hitting the phones hard doesn't fly anywhere) and are paying an additional monthly fee for another DID the cost is usually a wash anyways.
It's money exceptionally well spent to not have to worry about G.729 jitter and the nightmare that is analog>digital>analog>digital and back.
Not sure any notebook with sim card can do as not sure they take call.
Browsing the modern internet at 6kbs sounds painful.
When used in mobile phone networks, there are three different configurations (combinations of bitrates) that may be used for voice channels:
Configuration A (Config-WB-Code 0): 6.6, 8.85, and 12.65 kbit/s (Mandatory multi-rate configuration)
Configuration B (Config-WB-Code 2): 6.6, 8.85, 12.65, and 15.85 kbit/s
Configuration C (Config-WB-Code 4): 6.6, 8.85, 12.65, and 23.85 kbit/s*
A couple of years later I bought one of the first smartphones. It was a Kyocera Palm Phone. On it I could use the native Palm PPP dialer and again it would use the phone as a modem and just use my minutes. It worked pretty well, though the Palm browser was lacking. I mostly just used it for email.
The amusing thing was that apparently Verizon didn’t setup any sort of billing for my use-case, and since I never used the voice or text the thing just continued to work for a couple of years. It worked after the service cancelled, after the number was reclaimed, and then finally stopped only once the SIM card would no longer register on the network.
Not that I really cared - it was 9600 baud and I only used it a handful of times. Still a funny hack.
But you paid per minute (twice as much for 28k) and it was swiftly killed off by GPRS.
That was never deployed commercially in the US, it tied up too many channels. I was able to use CSD on T-Mobile and AT&T Wireless back in the day.
Worked well enough during unlimited nights and weekends to get on IRC.
* unlimited minutes,
* limited mobile data,
* many don't use their home phone, and
* their home internet is rate limited instead of data limited
So, what's stopping anyone (besides know-how) from getting unlimited (albeit slow) data by making a call to one's home computer, and using it as a proxy to get access to one's home internet service from anywhere?
All one needs is something to hookup their home computer to a phone-line.
I know people who talk on the phone for hours and hours. Doing so should be well within the realm of normal consumer use!
...and I am pretty certain I still have one or two old MultiTechs.
I need another project like I need a hole in my head.