Homelab analog telephone exchange
skagmo.com
skagmo.com
If I recall correctly, every-other class, they needed to decide which brother was going to be the designated recipient of the handed-down arcane design and maintenance knowledge. I believe the title of office was Phone Master, and just like Sith Lords, there were always 2: master and apprentice.
On the plus side, it had a photo sensor sitting over the washer and dryer display lights, so dialling the extension for the washer or dryer would give a busy tone if in use, and a ring tone otherwise.
> Built from relays that fell out of a Bell telephone truck by Fred Fenning while he was failing his telephony class, Tep-o-phone was a state-of-the-art telephone switching system that let the outside world dial individual rooms, switching tEp's six external lines. It also let people call the laundry room (Mr. Washer and Ms. Dryers) to see if there were free machines. Sadly, Tep-o-phone has since fallen into disrepair with the now-widespread use of cell phones, but every once in a while it tries to connect a call for old time's sake.
They did rig the laundry status up to the Internet, though, and you can confirm it from the same Zork-like interface in the laundry room.
It's an incredibly rare opportunity to see geek geezer volunteers keep this central office telephone switching equipment up and running, and they'll proudly show you how it all works. A combination of aging techs and students constantly maintain equipment ranging from crossbar switches to an ESS.
It's a labor of love, and you'll want to leave something in the tip jar just to say thanks.
It's high on my list of things to see in the US when I next get a chance to spend some time there (which could be several years away so I hope it keeps going strong).
As someone who has spent his career in networking and automation, it was fascinating to see the ingenious electromechanical ways people found to automate early circuit switching. In addition to the working step-machine, panel switch, and crossbar switches, they have a collection of teletypes and other miscellaneous curiosities. The power systems necessary to run the CO and provide dial tone to the area were also quite fascinating.
As an example, one of the small curiosities that particularly fascinated me was a device that read out the current time. This automated a minor facet of what human operators could do that the electromechanical switching systems could not: telling the current time.
https://www.aarp.org/work/careers/call-this-number-for-time-...
"What is the technology behind Sangoma Meet?" https://help.sangoma.com/community/s/article/What-is-the-tec...
> Sangoma Meet is based on WebRTC, which provides video conferencing and is supported by most of the major web browsers today.
> Our software stack is built upon several open source tools, including Jitsi Meet, FreeSWITCH™, HAProxy, Prometheus, Grafana, collectd, and other tools used for provisioning, deploying and managing the service.
FWIU, Sangoma Talk includes the Sangoma Meet functionality: https://www.sangoma.com/products/communications-services/tea...
> Mobile Soft Client: Take your company phone extension with you anywhere using a mobile soft client. Forward calls from the office, receive voicemails, start a video meeting, and much more! When you call your customers or clients through the Sangoma Talk app, they will see your office phone number, which allows you to maintain your personal device privacy. Available for iOS & Android devices.
GVoice (originally GrandCentral) can't do voice or video call transfer to the mobile soft client app, FWIU
You are correct that in the US, most personal/unlicensed (Part 95) radio services explicitly prohibit phone patch via FCC rule 95.349 [1]
[1] https://www.ecfr.gov/current/title-47/chapter-I/subchapter-D...
In the US the FCC will go after you for running half a watt over your power limit. In the UK, Ofcom literally cannot be paid to take an interest on what happens on amateur or ISM bands, and will only get involved if you're making a nuisance of yourself on commercially licensed frequencies.
But it might be using https://en.wikipedia.org/wiki/PMR446 which is open and licence exempt (though “base-stations” are prohibited).
Checkout lookmumnocomputer on YouTube.
He has some electromechanical exchanges in use at his museum... which has its own channel at thismuseumisnotobsolete
[1] https://www.microsemi.com/product-directory/signal-integrity...
The point of a modem is to translate data into an analog signal that can be decoded after going through a lossy transmission line, subject to bandwidth constraints and noise. The ADC introduces quantization noise, which affects the signal-to-noise ratio, but the same thing happens in a "real" phone line that goes over a digital trunk, and modems are designed to tolerate it.
Also, even if the connection quality is especially poor, modems are designed to perform a "line probing" algorithm, in which both ends of the connection will fall back to the slowest connection speed that can be reliably established.