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initial work on HOA retronetworking slides

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Retronetworking - Why, What and How
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:revealjsdir: /home/laforge/projects/git/reveal.js
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:author: Harald Welte <laforge@gnumonks.org>
:copyright: 2023 by Harald Welte (License: CC-BY-SA)
:backend: slidy
:max-width: 45em
== Who am I?
* Harald "LaF0rge" Welte
* Recovering Linux Kernel hacker (netfilter/iptables)
* Founder of Osmocom (Open Source Mobile Communications)
** tons of FOSS projects around mobile comms
* Active participant of CCC Camps and congresses since 1999
* Dayjob: Implementing cellular protocols across all layers
* Hobby: Research on data communications from the 1970s to 1990
** *Osmocom retronetworking* project was also operating ISDN + POTS at CCC Camp 2023
== Retronetworking
* many people enjoy *retrocomputing*
** focus is on historical computers (real or emulated)
* but what's a computer without communications technology?
* *retronetworking* is just like *retrocomputing*
** focus is on networking / telecommunications
== Why
* because we can
* relevance of communication technology to computing
** (at least) since the 1980s, home computers / PCs used accoustic couplers and modems
* equipment (user side, network side) readily available
** NICs, Modems, ISDN-TA, Video Telephones, Fax Machines
* personal reasons:
** I mostly was a user *back in the day*
** now I'm a developer with decades of experience
** no chance back then to play with / operate the network side
== Why (more serious reasons)
* our society becomes more and more technology-driven
* preserving [knowledge about] historical technology is important to preserve our *cultural history*
** thanks to Software Heritage Project, even software is now considered *immaterial cultural heritage* by
UNESCO
* today we still have a chance of collecting and/or documenting *early digital* communications technology
* window of opportunity is closing
** equipment harder to find once it is all scrapped
** software for management / configuration often even harder
** people involved in creating it are passing away
== What
* Applied protocol archaeology
* WAN
** PSTN
** ISDN
** CSPDN / X.21 / Datex-L / Teletex
** PSPDN / X.25 / Datex-P
** ATM
* Also: LAN (Arcnet, Token Ring, FDDI, ...)
== How (General Approach)
* collect old equipment, docs, cables, etc.
** disassemble, take PCB photographs
** dump any EEPROMs, flash cards, etc.
** publish everything on our wiki
* read (and scan!) manuals, protocol specs
* implement whatever is missing as FOSS / OSHW
== Minimal setup for playing with PSTN
* obtain some random PBX with analog FXS ports
* connect your Phones, Modems, Fax machines
* set up client machines (Terminal emulator, ...)
* set up server machines (BBS software, ...)
* dial server from client via PBX
* listen to modem sounds and experience the real thing
== Minimal setup for playing with ISDN
* obtain some random PBX with *internal* S0 ports
* connect your Phones, TAs, etc.
* set up client machines (Terminal emulator, ...)
* set up server machines (BBS software, ...)
* dial server from client via PBX
* make calls between ISDN video phones
== But: This is all *local*
* Running your PBX for PSTN or ISDN is all fine
* for real fun you'd usually want to *connect to other people remotely*
* Modem calls don't work very well over (most) SIP
** audio codecs (possible to force G.711)
** phase discontinuities due to different clocks
* ISDN data calls don't usually work over SIP
** RTP CLEARMODE should in theory support V.110/V.120/X.75
** different clocks still a problem
== Solution: Operate an *ISDN overlay network*
* Interconnect PBXs of different users via the internet
* use TDM-over-IP protocol to tunnel over the internet
* use GPS-DO to have identical clock on all sides
** avoids any cycle slips and reproduces synchronous networks like back in the day
* Hardware: Osmocom icE1usb as USB-E1-Adapter with GPS-DO
* Software: `osmo-e1d`, `DAHDI`, `yate`, etc.
== OCTOI Network
FIXME
== Joining OCTOI Network
* get a PBX with E1/PRI/S2M uplink
* get an icE1usb device + embedded Linux (rpi, beaglebone, nanopi, ...)
** icE1usb available with considerable community discount
* connect your system to the OCTOI hub
* interact with hosted services and/or other users
== OCTOI Event PBX
* we have 4 *OCTOI Event PBX* that can be used for retrocomputing/hacking events
* 3U 19" enclosure with
** Auerswald COMmander2 Basic PBX
** icE1usb + beaglebone
* just apply power, internet and (ideally) GPS
* connect PSTN + ISDN equipment
* have fun
== *real* ISDN/PSTN setup at CCC Camp 2023
* S0 bus / S interface restricted to 100m
* real ISDN user interface was Uk0 (up to 8km)
* providing this requires real subscriber line termination
* a friendly operator provided de-commissioned *V5 Access Network* equipment
** Nokia EKSOS
** Siemens Fastlink
** DeTeWe/Fujitsu ALIEN
* `osmo-v5` software to implement *LE* (exchange) side of V5 protocol stack
== Other technologies under research
* X.21 interface / CSPDN
** plan: USB-X.21 adapter for DTE/DCE/tracing
* Softmodems
** AMR-Riser carrier with iCE40 based USB audio class device
* Teletex
** plan: Software implementation of Teletex machine
== Rescuing an operational EWSD
* EWSD (Elektronisches WaehlSystem Digital) is a digital telephone switch
** used in >= 100 countries around the world
** primary digital telephony switch in German exchanges of the 80s/90s/00s
** competing alternative product is the *Alcatel S12*
** today virtually all of them switched off in German PSTN/ISDN
* To my knowledge, no telecom museum around the world has an operational EWSD
* jolly, nibbler and I want to rescue multiple
** first one goes to jolly's home
** if we manage to acquire more, they go to MSPT (German Communications Museum)
== Rescuing an operational EWSD
FIXME
== Rescuing historical technical literature
* retronetworking developed at a time where books/magazines were published on paper
* almost none of them could be found as eBook (commercially or "pirated")
* collecting books, magazines, manuals and other materials
* purchased a professional Zeutschel A2 Book scanner
* purchased a professional Canon A3 duplex sheet-fed scanner
* lots of destructive and some non-destructive scanning
* playing with tons of tools to figure out the best post-processing workflow
== Examples of the literature I scanned
* about 200 books so far
* Telekom Unterrichtsblaetter
* Jahrbuecher der Fernmelde-Praxis
* Mitteilungen aus dem FTZ
* Various FRG + GDR magazines on telecommunications
** Funk-Technik
** IK (Ingenieur der Kommunikationstechnik)
** NE (Nachrichtentechnik + Elektronik)
** Siemens Telcom Report
** Siemens Zeitschrift
** Signal + Draht
** TK - Telekommunikation
== Other fun retronetworking projects
* `osmocom-analog`: Analog trunked telephony
** Implements A/B/C-Netz, NMT, IMTS, AMPS, ... network side
** Allows use of historical analog cellphones
** fully functional
* CSD (circuit switched data support) in Osmocom CNI (GSM network)
** we should be able to get V.110 GSM-to-ISDN calls working!
** only very few weeks from completion
== Plan: Preserving oral history
* many of the engineers designing/implementing ISDN, ATM and other technologies are still alive
* they can tell exciting stories, anecdotes, etc. you will find in no book
* let's try to record interviews with them to record the *oral history*
* window of opportunity is closing due to advanced age of many protagonists
* help wanted!
== Wet dream: SDH at a hacker event?
* `gruetzkopf` and I collected plenty of SDH equipment
** I can run STM-1 over single mode between rooms in my house
** not very exciting due to limited size/scope and usage
* Idea: create a STM-1 ring around a CCC event (congress, camp)
* used add-drop multiplexers to provide E1 (PRI)
** for E1/PRI connectivity to users
** for back-haul of V5 access networks (ISDN/PSTN user ports)
** possibly even for the GSM team (macro BTS)
* equipment exists, *just* needs more interested hands
== How to Help?
* document any retronetworking technology you may have
** pictures, manuals, EEPROM images, ...
* identify and reach out to contemporary witnesses
* collect and/or scan books/magazines
* obtain/preserve equipment disposed at telcos and other enterprises
* volunteer at museums (like MSPT collection in Heusenstamm near FFM)
* build more services that can run on top of OCTOI
== How to get in touch?
* join our forums at https://discourse.osmocom.org/
* join our IRC channel `#retronetworking` on `libera.chat`
* join our (almost) monthly teleconference `RetroNetCall`
* contact me privately if you have stuff to donate
** e-mail: `laforge@gnumonks.org`
** Fediverse: `@LaF0rge@chaos.social`
== Further Reading
* https://osmocom.org/projects/retronetworking/wiki
* https://osmocom.org/projects/octoi/wiki
* https://projects.osmocom.org/projects/retronetworking/wiki/RetroNetCall
[.questions]
=== !
[.bubbles]
=== !
[.hands]
=== !
== EOF
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