Open Source Mobile Communications

During the past months, the primary focus in the project was on setting up reliable ISDN PRI services via the OCTOI protocol and the related hub ("central office").

Today, we've tested yet another service over OCTOI: IP in HDLC. This broadband technology doesn't use individual 64kbps E1 timeslots like in ISDN, bug it aggregates the entire 31 timeslots of the E1 link (exept for TS0) into one fat HDLC pipe. It is customary to either put raw IP packets, or Ethernet packets, or PPP frames or even Frame_Relay into that HDLC. These method of operation is supported by a variety of routers from the 1990ies.

We've tested two configurations:

Pysical E1 on client side, virtual E1 (dahdi-trunkdev) on hub side¶

In this configuration, an overall inner RTT of 150ms was achieved, a 115ms increase compared to the native underlying IP link.

virtual E1 (dahdi-trunkdev) on both client and hub side¶

In this configuration, an overall inner RTT of 108ms was achieved, a 73ms increase compared to the native underlying IP link.

We're happy to announce the next incarnation of OsmoDevCall

This time, laforge will be presenting an Osmocom Community TDMoIP (OCTOI)

When: Friday, April 29, 2022 from 20:00 CET

Time	Topic	Who
20:00	Meet and Greet	everyone
20:10	Osmocom Community TDMoIP	laforge
21:00	USSE (Unstructured Supplementary Social Event)	everyone

Where: https://meeting5.franken.de/b/har-xbc-bsx-wvs (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).

We're happy to announce the next incarnation of OsmoDevCall

This time, Sec and schneider will be presenting an Iridium reverse engineering update

When: Friday, March 25, 2022 from 20:00 CET

Time	Topic	Who
20:00	Meet and Greet	everyone
20:10	Iridium reverse engineering update	Sec, schneider
21:00	USSE (Unstructured Supplementary Social Event)	everyone

Where: https://meeting5.franken.de/b/har-xbc-bsx-wvs (Big Blue Button of https://franken.de/)

NOTE: There will be no recording of this talk. If you're interested, you have to participate live!

We're happy to announce the next incarnation of OsmoDevCall

This time, tsaitgaist will be presenting on USB-C - the connector and USB-PD

When: Friday, March 11, 2022 from 20:00 CET

Time	Topic	Who
20:00	Meet and Greet	everyone
20:10	USB-C - the connector and USB-PD	tsaitgaist
21:00	USSE (Unstructured Supplementary Social Event)	everyone

Where: https://meeting5.franken.de/b/har-xbc-bsx-wvs (Big Blue Button of https://franken.de/) NOTE: URL has changed recently

Yesterday, laforge and manawyrm have managed to establish the first successful calls between two ISDN PBX interconnected via the Proposed_efficient_TDMoIP protocol implemented in osmo-e1d using the icE1usb hardware.

The setup looks as follows:

Using this setup we could validate so far:

• the new, efficient and transparent OCTOI TDMoIP protocol works over public consumer internet access (VDSL on one end / DOCSIS on another end)
• GPS-locked oscillators on both sides provide stable shared clock for cycle-slip free operation

Contrary to other established TDMoIP protocols, it is both transparent / protocol-agnostic and only transmits those timeslots of a E1 PRI circuit that are in use.

We are therefore fairly certain that this setup can be the basis of the larger intended Community_TDMSS7_Network we have in mind. There is lots of work to do, and we appreciate any help (see project issue tracker).

We're happy to announce the next incarnation of OsmoDevCall

This time, laforge will be presenting on Advanced SIM card topics: GlobalPlatform SCP02, OTA, ARA-M, ISIM

The talk covers some of the more advanced topics related to SIM cards:

• GlobalPlatform commands / SCP02 protocol
• OTA (Over The Air) RFM/RAM via TS 03.34
• The ARA-M applet
• The ISIM application

It is expected that the audience is familiar with SIM card basics, such as SIM/UICC/USIM concepts and the general file system abstraction.

When: Friday, February 25, 2022 from 20:00 CET

Time	Topic	Who
20:00	Meet and Greet	everyone
20:10	Advanced SIM card topics: GlobalPlatform SCP02, OTA, ARA-M, ISIM	laforge
21:00	USSE (Unstructured Supplementary Social Event)	everyone

Where: https://meeting5.franken.de/b/har-xbc-bsx-wvs (Big Blue Button of https://franken.de/) NOTE: URL has changed

We're happy to announce the 23nd incarnation of OsmoDevCall

In this edition, we will not have any presentation, as sadly nobody has volunteered to present this time. Nevertheless, we still hold the call in case anyone wants to chat about random stuff.

When: Friday, February 11, 2022 from 20:00 CET

Time	Topic	Who
20:00	Meet and Greet	everyone
20:10	USSE (Unstructured Supplementary Social Event)	everyone

Where: https://meeting5.franken.de/b/har-xbc-bsx-wvs (Big Blue Button of https://franken.de/) NOTE: URL has changed!

The pySim source code has contained built-in sphinx based documentation for quite some time, but users had to build the manual locally from source.

A HTML rendering of the [latest git master] pySim user manual is now published at https://downloads.osmocom.org/docs/latest/pysim/ - it is automatically updated via our jenkins CI.