Retronetworking

We're happy to announce the next incarnation of RetroNetCall, the retronetworking oriented spin-off of OsmoDevCall

This time, laforge will be presenting on Teletex: Between Telex and Telefax.

Everyone knows Telefax, and most people will have heard what Telex was. Few people are aware of the designated intermediate system Teletex. It was used like a "remote type writer", where formatted pages of (monospaced) text could be entered, transmitted and printed by a remote typewriter.

When: Wednesday, June 7, 2023 from 20:00 CEST

Where: https://osmocom.org/RetroNetCall (Big Blue Button of https://franken.de/)

We're happy to announce the next incarnation of RetroNetCall, the retronetworking oriented spin-off of OsmoDevCall

This time, tnt will be presenting part 1 of E1: The analog side.

Many of us know E1 circuits from ISDN or GSM A-bis, and are familiar with the digital side of them. Building a related E1 interface mostly uses [still] available LIU (Line Interface Unit) integrated circuits. tnt took it one step further and started to think along the lines of what if I had to do my own LIU analog circuit design?

When: Wednesday, May 3, 2023 from 20:00 CEST

Where: https://osmocom.org/RetroNetCall (Big Blue Button of https://franken.de/)

We're happy to announce the next incarnation of RetroNetCall, the retronetworking oriented spin-off of OsmoDevCall

This time, laforge will be presenting an Introduction to the X.21 interface.

For more background see X21.

• electrical signals
• signal timing
• call signaling

When: Wednesday, March 1, 2023 from 20:00 CET

When: Wednesday, March 1, 2023 from 20:00 CET

Where: https://osmocom.org/RetroNetCall (Big Blue Button of https://franken.de/)

We're happy to announce the next incarnation of RetroNetCall, the retronetworking oriented spin-off of OsmoDevCall

This time, laforge will be presenting on DATEX-L, the German circuit-switched public data network which existed from 1967 (!) onwards.

For more background see CSPDN__Datex-L.

• timeline / history
• network architecture
• applications

When: Wednesday, February 1, 2023 from 20:00 CET

Where: https://osmocom.org/RetroNetCall (Big Blue Button of https://franken.de/)

We're happy to announce the next incarnation of RetroNetCall, the retronetworking oriented spin-off of OsmoDevCall

This time, there will be no technical presentation, just an opportunity for retronetworking interested folks to meet and chat.

When: Wednesday, January 4, 2023 from 20:00 CET

Where: https://osmocom.org/RetroNetCall (Big Blue Button of https://franken.de/)

We're happy to announce the next incarnation of RetroNetCall, the retronetworking oriented spin-off of OsmoDevCall

This time, laforge will be presenting on ISDN B-channel protocols: V.110, V.120, X.75, H.221

• description of the respective protocol
• look at a protocol trace
• status of open source implementations

When: Wednesday, December 7, 2022 from 20:00 CET

Where: https://osmocom.org/RetroNetCall (Big Blue Button of https://franken.de/)

We're happy to announce the next incarnation of RetroNetCall, the retronetworking oriented spin-off of OsmoDevCall

This time, laforge will be presenting a General status update on OCTOI (Osmocom Community TDMoIP)

• migation to co-located hub now fully completed
• osmo-e1d status update
• the new osmo-isdntap project for tracing/recording D and B channel data
• Some initial research into H.221 / dissecting video calls
• OCTOI BERT problems
• 4x new Octoi_Event_PBX for rapid deployment of ISDN+POTS at various events
• yate troubles regarding missing call.answer when using record/playback
• resuming work on the BRI interface

When: Wednesday, November 9, 2022 from 20:00 CET

Where: https://meeting5.franken.de/b/har-0y1-wch-et4 (Big Blue Button of https://franken.de/)

Thanks to Fritz Elfert, we were able to acquire a full CVS backup of the no-longer-accessible CVS server cvs.isdn4linux.de.

We manually created mapping tables for CVS user names to real names / e-mail addresses and used cvs2git to import those into git repositories for contemporary viewing, analysis and long-term archieval.

The results can be found in our gitea, individual repositories linked below:

• capi4linux (original CVS name NC4Linux)
• isdn4linux (original CVS name isdn)
• idsn4k-utils (use cvsimport branch)
• isdnfax
• mISDN
• mISDNuser (use cvsimport branch)
• web

In case you're interested in the above, you might also be interested in our previous re-construction of the u-isdn history

Osmocom developer jolly has started a new project for implementing the central-office side of the ISDN U (Uk0 in Germany) interface using a sound card with 192kHz samplerate.

Using this setup, you can connect an ISDN NT for BRI (NTBA in Germany) to your sound card, and provide ISDN services via mISDN.

Some basic information about a first proof-of-concept can be found at Software_Defined_Uk0; stay tuned for more information.

There is no real documentation yet on how to reproduce this, but code can be found at https://gitea.osmocom.org/retronetworking/uk0 (SDR PHY for Uk0) and https://gitea.osmocom.org/cc/osmo-cc-misdn-endpoint/src/branch/jolly/uk0 (mISDN port to make use of the former).

A number of previously unavailable historical German national standards related to (mainly) ISDN have been uncovered and are now availale as PDFs from https://people.osmocom.org/laforge/ftz/ (and in more structured presentation with metadata at German_FTZ_ISDN_Specifications).

• 1TR6 - German National ISDN variant of the 1980ies, before Euro-ISDN was introduced in the 1990ies
• 1TR7 - German National SS7 dialect
• various physical layer specs for interfaces such as S2M, V2M, Uk0, Uk2, UG2 and more