VOGONS


Reply 20 of 51, by 486man_

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Thanks for good post on an interesting subject. I have to try VOIP gateway and/or Cisco router at some point as they sound interesting. Based on your post I assume the VOIP gateways can be used as "poor mans PBX" to interconnect two modems in such a way that doesn't break modem communication (without or with proper VOIP coding). And generate RING signal of course.

As a side note you dont need "phone line simulator" kind of device at all if both of following conditions are true
a) at least one of the modems is USR courier
b) you have a way to make the "server side" modem answer without RING signal

I have used USR courier as server side modem. You can program the data/voice button to execute arbitrary at command. Of course here the command would be ATA. After dialling out with client (e.g. atx3dt123456 or just atx3d) you would hit the button and listen modems handshaking (the beautiful sound). After completing the handshake PPP (or slip) takes place.

Here's my other post Internet with retro PC and HW

Unfortunately I didn't find your tutorial when building my setup.. 😒

Reply 21 of 51, by 3dnow

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Why use a VOIP module as a central office replacement in the first place? Even with the G.771 codec, the connection quality for analogue modems will always be inferior to a proper powered phone line.
By sacrificing automatic answering, and instead manually answering on the server with the ATA command, there is no need for dial tones or a ringer since only power is needed for off-hook devices to communicate.

If you are only using analogue modems for both the server and client (so 33.6 Kb/s with the V.34 standard) then only a 9V D/C power source is needed to power the line. This could come from a 9V A/C adapter though batteries offer the cleanest D/C power delivery. A better use for the VOIP module would be to plug a RJ11 splitter into an available port and simply use it for power. For the DIY option there are some guides for building a "Line voltage inducer" by splitting open a phone cable and adding a 9V battery (2 in series for 18V if you are European) and resistor to the circuit.

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Instead of a single 9V battery I used 8 AAs in series adding up to 9.6V D/C.
Remember rechargeable NiMH AAs are only 1.2V. If you are using 1.5V Alkalines then only 6 in series is safe.

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Also instead of using Windows I find it much easier to setup a dial-up server using Linux with mgetty and PPP.
My server is a Rasberry Pi 400 with a Dell Connexant RD02-D400 56K V.92 USB Modem and the client is using a US Robotics 5686G 56K V.92 Faxmodem connected with a serial to USB adapter. For stability I transferred a 300 MB ISO file from the server to the client using Minicom, and over the course of 23 and a half hours the connection did not drop or retrain to a lower speed.

Reply 22 of 51, by 3dnow

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Here is a speed test:

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I'd like to get a second USR modem for a internet speed closer to 33.6k, although when using Hyperterminal and Minicom for file transfers I tend to get speeds very close to the maximum for the V.34 standard.

Reply 23 of 51, by Cloudschatze

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3dnow wrote on 2024-12-30, 02:29:

By sacrificing automatic answering, and instead manually answering on the server with the ATA command, there is no need for dial tones or a ringer since only power is needed for off-hook devices to communicate.

There's no need to sacrifice auto-answering in a direct, modem-to-modem scenario where the target is Linux-based. Since you're using mgetty, just throw something like the following into the mgetty.config file:

post-init-chat "" ATS7=15 OK ATM0A ""

...which, in conjunction with the respawning behavior of the mgetty service (restart=always), will result in the modem attempting to auto-answer every 15-seconds (and with the speaker muted, if the modem has one).

Reply 24 of 51, by 3dnow

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Cloudschatze wrote on 2024-12-30, 04:48:

There's no need to sacrifice auto-answering in a direct, modem-to-modem scenario where the target is Linux-based. Since you're using mgetty, just throw something like the following into the mgetty.config file:

post-init-chat "" ATS7=15 OK ATM0A ""

...which, in conjunction with the respawning behavior of the mgetty service (restart=always), will result in the modem attempting to auto-answer every 15-seconds (and with the speaker muted, if the modem has one).

I did not know that mgetty allowed for repeatedly answering the modem like that. Could be worth a try. Also just received a second USR 5686G in the mail today, and I'm going to replace the Dell Conexant modem with it which should hopefully provide better performance (hopefully the best performance with V.34).

Reply 25 of 51, by 486man_

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Thank you very muh for this mgetty hint! I ran pppd directly on the (usb) serial device and used the ATA-programmed voice/data button to answer. And btw with courier you dont need the battery either. Luckily I saved half dozen couriers (v.everything + one 2400e) and sportsters (v.34) from ending up in dumpster 20+ years ago 😀

I do have a question. There exista a large amount of telnet based bbs services. To bring 90s memories even closer i have tried to download files from these bbss' with zmodem to telix running on dos. So like this
- 486 pc, dos 6.2, telix, sportser modem
- dialup to linux shell (no ppp or slip)
- telnet (-8) to bbs (ansi colors etc do work)
- start zmodem download

The result is that telix correctly starts zmodem receiver but after a while ( maybe 15-30 secs) telix starts complaining about zmodem crc errors and the transfer fails.

I assumed this is because linux receives data from bbs/internet with much higher throughput than it can send over 33,6 modem line. But I have tested also policing the internet -> linux link with tc to under 33,6k and it does not help. I would appreciate if anyone could advice me on this.

Reply 26 of 51, by 3dnow

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I managed to score a brand new and never unboxed USR V.Everything 56k Courier modem (Model 3453C) for less than $50. It was a real treat to unbox, plug everything in, and program it with the AT commands.

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Unfortunately I ran into problems getting it to connect and handshake with my other modems. Initially it was due to me plugging the RJ11 connector into the phone port instead of the line out port (Look guys I may be an idiot, but at least I'm not stupid). But even after using the correct port the Courier would either immediately disconnect and report "No Dial Tone", or it and the other modem would stumble over each other sending improperly timed audio signals (The Courier thinks that the handshake initiation from the other modem is a CO dial tone and responds with the DTMF number tones and ruining the handshake). Having the other modem dial and manually answering the courier with ATA did not work either. I ran the internal loop-back analogue diagnostics (AT&M0&N3S14.0=0 to enter testing mode. Then AT&T1 for analogue loop-back mode, or AT&T8 to run a test pattern from the transmitter to the receiver.) but both showed that the modem was perfectly functional.

Later when visiting my parents I used their landline and the Courier would dial numbers properly. I even connected to the BBS at https://bbs.retrobattlestations.com/. It seems to me that USR Courier modems require a dial tone from a CO even when blind dialing is enabled with ATX3 or ATX5. This is strange considering my USR 5686G external serial modem, all my USB modems, and even an old Conexant PCI winmodem all support blind dialing and answering. Anyone else know about this?

I'm planning on getting an analogue PBX or PABX of some kind to connect all my machines that have modems, so this won't be an issue for much longer; but does anybody know how to properly enable blind dialing on a model 3453C US Robotics Courier?

Reply 27 of 51, by matti157

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These days I am trying a little variation, having 2 devices is inconvenient (the Cisco router + the VOIP POTS).
So I bought for 20€ a Cisco 2921 and for 15€ a VIC3-4FXS card.

With the right configuration I should be able to make it work as a dialup server, without having the dual device

Reply 28 of 51, by 3dnow

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I managed to acquire an analog PABX with eight extension lines for cheap. Now all my machines with modems can call each other without having to split anymore phone lines and use batteries. The courier modem also works perfectly and I found a second in good shape for around $25.

The private telephone exchange unit is the Excelltel MS208 PABX with two CO lines (three but one is disabled unless you get the model with three CO lines) and eight extension lines. It's cheap at around $45, but you may need to order from China directly since it's rarely on Ebay or Amazon at a decent price. The line quality is far superior to a VOIP ATA and cost significantly less than a telephone line simulator.

I'm considering getting a VOIP ATA later and connecting it to one of the CO ports so that I can dial up to some BBS's.

Reply 29 of 51, by davidrg

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Using a PBX is certainly the easy path if you can get one cheap/free. Several months back I fetched out of storage an old Panasonic KX-TD1232 I got for free a some point years ago, works great. Provides all the normal tones (dial, busy, off hook, etc) and modems just work. Only real fault I can find with it so far (aside from its size) is it only allows three digit phone numbers.

For the "ISP" end, I've got an old Raspberry Pi with a 16 port USB Serial thing that I've been using as a terminal server for the last few years. Just plugged a modem into one of its ports, setup mgetty, and now any vintage OS can happily dial in and get internet - even OS/2 Warp 3 that has no LAN support at all:

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My next challenge when I've got the time: the PBX has a BRI line card in it that can supposedly be configured as extension lines, and I've got a BRI server card that can accept V.90 calls over ISDN. Maybe I can figure out all the pieces and if the PBX does the analog/digital conversion properly I get 56k dialup.

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Reply 30 of 51, by 3dnow

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davidrg wrote on 2025-01-14, 18:16:

My next challenge when I've got the time: the PBX has a BRI line card in it that can supposedly be configured as extension lines, and I've got a BRI server card that can accept V.90 calls over ISDN. Maybe I can figure out all the pieces and if the PBX does the analog/digital conversion properly I get 56k dialup.

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If the BRI-ISDN digital extension can interface with the analog extensions then your digital to analog conversion is covered.
Hopefully your PBX is capable of emulating a digital ISDN CO like how it emulates an analog CO, otherwise you will need an ISDN line simulator between the server card and PBX. ISDN line simulators are very expensive (more than analog line simulators which are already expensive), and there is no known way to DIY them unlike with analog lines.

Reply 31 of 51, by Jo22

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3dnow wrote on 2025-01-15, 04:42:

ISDN line simulators are very expensive (more than analog line simulators which are already expensive), and there is no known way to DIY them unlike with analog lines.

Some of the German Fritzbox DSL/Cable routers do have an S0 bus, so digital ISDN telephones can be attached.
The model 7590 AX, for example. There are two versions (ISDN and non-ISDN).

"Time, it seems, doesn't flow. For some it's fast, for some it's slow.
In what to one race is no time at all, another race can rise and fall..." - The Minstrel

//My video channel//

Reply 32 of 51, by davidrg

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3dnow wrote on 2025-01-15, 04:42:

If the BRI-ISDN digital extension can interface with the analog extensions then your digital to analog conversion is covered.
Hopefully your PBX is capable of emulating a digital ISDN CO like how it emulates an analog CO, otherwise you will need an ISDN line simulator between the server card and PBX. ISDN line simulators are very expensive (more than analog line simulators which are already expensive), and there is no known way to DIY them unlike with analog lines.

The PBX manual describes how to configure one or more of the BRI lines (there are six) as extension lines rather than CO lines, and discusses hooking up digital phones and computers to the S0 bus. It doesn't say you you can call from regular to ISDN extensions, but it also doesn't say you can't and as its proprietary phones are digital (its a "Digital Super Hybrid" PBX) its already having to support analog to digital calls so it would be a bit silly if it didn't also support analog to ISDN calls.

The main problem at the PBX end right now is that the manual assumes you've already been on all the training courses and have good familiarity with ISDN. I've received no training, and this is the first piece of ISDN equipment I've ever encountered (besides the onboard ISDN interface in the SGI Indy, but I've never seen or attempted to make that do anything). At the moment calling from an analog or digital proprietary phone to an ISDN extension just results in a busy signal - maybe I've configured it wrong, or maybe its because it can sense nothing is actually hooked up to any of the ISDN extensions right now.

The next step is getting the Dialogic Diva to do something. Back in November I had a go at setting up a pair of them in a small MicroATX 500MHz Celeron PC running the last 32bit release of Debian the drivers claim to support, and the drivers install fine, but they just throw out an error on startup. Maybe they're compiled for a newer CPU? might have to try and find some older drivers (and an older version of Linux), or give up and put Windows Server on the thing just to at least confirm the hardware itself is working ok.

Reply 33 of 51, by Veeb0rg

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Right now I use a Cisco 2821 with a WIC-2AM, VIC3-FXS and a VIC3-FXO card in it with an ATA-191 for VOIP access. I have a Radius VM setup for access control. Works very well. If you dial in with PPP you get PPP and internet, if you dial in with just a terminal you telnet to my BBS. I had this setup in a 2811 but moved to the 2821 after I swapped the 80mm fans to quieter ones. Its now nearly silent. I'm sure there's a way to loose the ATA box and connect the VOIP with the cisco directly but the ATA box was just easier for now.

I just purchased the new "upgrade" for my little DIY ISP. I've bought a Cisco IAD2432 and an Equinox Digital Modem pool. I should now be able to have 56k capable connections. I'm going to stand up an Asterisk server for PBX duty.

Last edited by Veeb0rg on 2025-01-15, 07:11. Edited 1 time in total.

Reply 35 of 51, by matti157

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Veeb0rg wrote on 2025-01-15, 06:56:

Right now I use a Cisco 2821 with a WIC-2AM, VIC3-FXS and a VIC3-FXO card in it with an ATA-191 for VOIP access. I have a Radius VM setup for access control. Works very well. If you dial in with PPP you get PPP and internet, if you dial in with just a terminal you telnet to my BBS. I had this setup in a 2811 but moved to the 2821 after I swapped the 80mm fans to quieter ones. Its now nearly silent. I'm sure there's a way to loose the ATA box and connect the VOIP with the cisco directly but the ATA box was just easier for now.

I just purchased the new "upgrade" for my little DIY ISP. I've bought a Cisco IAD2432 and an Equinox Digital Modem pool. I should now be able to have 56k capable connections. I'm going to stand up an Asterisk server for PBX duty.

What do you need the FXO board for?

Reply 36 of 51, by Veeb0rg

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matti157 wrote on 2025-01-15, 13:51:
Veeb0rg wrote on 2025-01-15, 06:56:

Right now I use a Cisco 2821 with a WIC-2AM, VIC3-FXS and a VIC3-FXO card in it with an ATA-191 for VOIP access. I have a Radius VM setup for access control. Works very well. If you dial in with PPP you get PPP and internet, if you dial in with just a terminal you telnet to my BBS. I had this setup in a 2811 but moved to the 2821 after I swapped the 80mm fans to quieter ones. Its now nearly silent. I'm sure there's a way to loose the ATA box and connect the VOIP with the cisco directly but the ATA box was just easier for now.

I just purchased the new "upgrade" for my little DIY ISP. I've bought a Cisco IAD2432 and an Equinox Digital Modem pool. I should now be able to have 56k capable connections. I'm going to stand up an Asterisk server for PBX duty.

What do you need the FXO board for?

For the ATA device/VOIP interface.

Reply 37 of 51, by Veeb0rg

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matti157 wrote on 2025-01-15, 13:50:

I read this tutorial for 56K, for me is too much 😥
https://web.archive.org/web/20240716065145/ht … 6k-dial-up.html

Yeah, unless you come across a deal its pretty expensive to get a 56k connection going. Digital modem stuff has gotten crazy expensive the last few years.

Reply 38 of 51, by 3dnow

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Veeb0rg wrote on 2025-01-15, 20:54:
matti157 wrote on 2025-01-15, 13:50:

I read this tutorial for 56K, for me is too much 😥
https://web.archive.org/web/20240716065145/ht … 6k-dial-up.html

Yeah, unless you come across a deal its pretty expensive to get a 56k connection going. Digital modem stuff has gotten crazy expensive the last few years.

Lucky you getting that digital modem pool to go with your router. For now I'm going to stick with 33.6k. My current project is creating a dial-up file server protected by a USR Courier with dial security.

Reply 39 of 51, by Veeb0rg

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3dnow wrote on 2025-01-16, 05:39:
Veeb0rg wrote on 2025-01-15, 20:54:
matti157 wrote on 2025-01-15, 13:50:

I read this tutorial for 56K, for me is too much 😥
https://web.archive.org/web/20240716065145/ht … 6k-dial-up.html

Yeah, unless you come across a deal its pretty expensive to get a 56k connection going. Digital modem stuff has gotten crazy expensive the last few years.

Lucky you getting that digital modem pool to go with your router. For now I'm going to stick with 33.6k. My current project is creating a dial-up file server protected by a USR Courier with dial security.

It was, I didn't expect them to take the offer I made. Then I was concerned because I couldn't find any documentation on it. Turns out on one of the discords I am on someone had all the software and manuals for the thing. It doesn't have a onboard terminal server so I'll need to run a pc to handle that but otherwise I'm hopeful!