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Build your own Dial-up ISP with a Raspberry Pi

jeffgeerling.com

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Re: Build your own Dial-up ISP with a Raspberry Pi

#4

Post by kotaKat »

I feel like it would have been more fun to build your own line simulator with a 9 volt battery and some old phone line and just skip the dialtone altogether for a little magic... the $120 black-box telco simulator takes a lot of the fun out.

But then again, based on Pi pricing today, the $120 telco simulator goes nicely with a $300 Pi 5.

Re: Build your own Dial-up ISP with a Raspberry Pi

#5

Post by alnwlsn »

If you ever want more phone lines than that, you can pick up an old Cisco VG-224 from Ebay for less than half the price of that line simulator, and you get 24 lines. There is a configuration that will let you use it as a standalone unit where all the lines can call each other with custom phone numbers (here's some notes [1]).

The main catch is that they have a 50-pin Centronics style connector on them which you will have to break out somehow to your RJ11s. Also, they are big (1U rack) and have fans.

I've got a few of these and have been meaning to set them up with a bunch of modems and a bunch of computers, but haven't gotten to it yet. Modems do seem to work in the limited testing I've done. They do (as expected) work great with telephones, including pulse dialing.

[1] https://alnwlsn.com/z/pots/cisco-vg224.html

Re: Build your own Dial-up ISP with a Raspberry Pi

#6

Post by giantrobot »

kotaKat wrote: post #4

I feel like it would have been more fun to build your own line simulator with a 9 volt battery and some old phone line and just skip the dialtone altogether for a little magic... the $120 black-box telco simulator takes a lot of the fun out. But then again, based on Pi pricing today, the $120 telco simulator goes nicely with a $300 Pi 5.

Line simulators are fun. The ports can call each other and there's no need to set any custom init strings on the modem like you need with the 9 volt trick. For some old devices that's a necessity.

You can also use an old VoIP ATA from Linksys/Cisco as a cheap line simulator. Like a fully analog TLS the ports can call each other. They can be a PITA to configure right but they're cheap and work well enough.

I've used all three methods, the TLS is the easiest. An ATA can be useful if you've got more than one and your dial-in server is in a different room from the client you're playing with. An ATA can also be set to "call" another device. So your office ATA can call the basement ATA (with your Linux server) as an example.

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