Phone Line Emulator Idea

[mojorific]

Not that I have the capabilities to make this, but it would be fantastic if someone would make the following:

A device which takes standard phone plug input, and ethernet and acts as a phone line to ethernet/internet emulator.

You would program it with a list of phone numbers and matching IP addresses to actual BBS's on the internet, and then hook it up to your vintage computer and your internet router.

When set up, you would use your old computer to unhook the phone, get an emulated dial tone from the device, and then dial the number to a BBS (which would be translated to an IP address on the device) using the actual modem.

It would ring, make all that connection noise you would expect, and then connect to the ip address. Thus, directly connecting your analog modem to an internet BBS via IP address.

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Sounds complicated, but it would allow you to have a vintage computer work as intended back in the 80's/90's - with a real dialtone, real sounds, and the actual modem. As most BBS's are internet based now, this would be a great thing to have.

I know i'm probably dreaming, but it would be amazing if something like this could be built for us vintage computer collectors.

 

[Chuck(G)]

You'd have to add a random noise generator to it to simulate the state of phone comm in the 80s.

 

[antiquekid3]

Digium makes some hardware that will do that. I've got an 8-port FX card in my PC running Ubuntu with FreePBX. I have successfully dialed-up to a BBS on a 300 baud acoustic coupled modem with a 1955 Western Electric 500. Digium had a product at one time that was literally what you describe: a single Ethernet jack, a phone jack, and a power plug. It was called the IAXy, as I recall.

 

[SkydivinGirl]

Wouldn't lag be the biggest issue with these types of devices? I generally use one of the Lantronix adapters in modem emulation mode. I believe you can even use DNS names instead of IP addresses. This would allow you to set your BBS numbers as DNS entries that point to IP addresses.

Heather

 

[glitch]

Digium had a product at one time that was literally what you describe: a single Ethernet jack, a phone jack, and a power plug. It was called the IAXy, as I recall.

Yup, and these are super-cheap now since they're EOL. I've got a few of them kicking around. You'd still need a PBX to connect with. It's probably possible to write an Asterisk module to make a connection to a Telnet destination, encode both the send and receive strings as (pick your revision) modem audio, and send it down the phone line.

 

[g4ugm]

Such a device is general known as an ATA or Analogue Telephone Adaptor and there are many available...

There is whole network of folks with real phones over IP C*NET see https://www.ckts.info/ for info. Pretty sure most of this is applicable to networking up to 300 baud...

 

[glitch]

There is whole network of folks with real phones over IP C*NET see https://www.ckts.info/ for info. Pretty sure most of this is applicable to networking up to 300 baud...

I've wanted to try a modem connection over private VoIP lines, haven't gotten around to doing it. RetroHacker_ and I have experimented with modem connections through my Asterisk PBX, both internal and to the PSTN. Internal is fine, but we ran into issues with going out to the PSTN. Never got so far as to determine whether it was a timing issue or a result of SIP service providers' aggressive compression.

 

[Ole Juul]

I've wanted to try a modem connection over private VoIP lines, haven't gotten around to doing it. RetroHacker_ and I have experimented with modem connections through my Asterisk PBX, both internal and to the PSTN. Internal is fine, but we ran into issues with going out to the PSTN. Never got so far as to determine whether it was a timing issue or a result of SIP service providers' aggressive compression.

G711 does not use compression, so use that. From my own experiments I still can't tell if µ-law and A-law is better. A-law needs less processing power but I don't think that is generally an issue for our uses. For voice, G729 apparently gives results which are indistinguishable in clarity to G711, but the signal is indeed highly compressed and not suitable for data.

I assume you already know how to deal with echo cancellation and jitter buffering since those parameters are much discussed. However, RTP packet size is something which is less known about. The default is typically 20 or 30, but smaller could be good. I don't know yet. A smaller RTP will use more bandwidth but I don't think there is any harm in that, and the benefits may be useful.

 

[NF6X]

I would like to have a box which does pretty much what mojorific describes, but it uses WiFi for its network connection and it's smart enough to automatically jump through any extra login hoops necessary to get online. This box would know how to log in to the WiFi at places like Starbucks or McDonalds, and it would translate either pulse or tone dialing into commands to connect up to Telnet BBSes and the like. Then, I could rock machines like my Model 100, Model 4P with an internal modem, etc. at the local Starbucks!

I could build that, but I have way too many projects on my list to ever get around to doing it in real life.