Hello FreeCalypso community, I just put out a new release of FC host tools:
ftp://ftp.freecalypso.org/pub/GSM/FreeCalypso/fc-host-tools-r19.tar.bz2 ftp://ftp.freecalypso.org/pub/GSM/FreeCalypso/fc-host-tools-latest.tar.bz2 (symlink) and new official stable firmware builds for FreeCalypso modems: ftp://ftp.freecalypso.org/pub/GSM/FreeCalypso/fcdev3b/fcdev3b-prod-fw-20230608.tar.bz2 ftp://ftp.freecalypso.org/pub/GSM/FreeCalypso/Tango/tango-modem-fw-20230608.tar.bz2 FC host tools noteworthy changes: the only truly interesting changes from r18 to r19 involve rvinterf logging. If you are interested in tracing primitive exchanges between protocol stack components, as described in the Frame Users Guide document from TI, the new version of rvinterf has its max Rx packet length limit raised to match what the firmware can send, and the new session log format is more sensible and useful. Another logging-related change that should be readily noticeable is that non-printable bytes mixed into places where ASCII strings are expected are now printed in C-style backslash escape form, rather than 'cat -v' form. Modem firmware changes since the last official build dated 20210811: 1) New AT%MSCAP and AT%SPVER commands, documented in the new Speech-codec-selection article in freecalypso-docs, allow you to modify the speech version list sent to the network in the Bearer capability IE for both MO and MT voice calls, thereby telling your local GSM operator's network "alternative truths" about which codecs your MS supports. Using this feature, you can determine experimentally how your network handles GSM MS that don't support AMR (FreeCalypso does support AMR, but with the new feature you can lie to the network and say that it doesn't), and at least in my part of the world such Bearer cap IE manipulation is the only way to coax the network into giving you TCH/FS or TCH/EFS rather than TCH/AHS. 2) Once you do get a non-AMR speech TCH out of your network (whether by doing the above manipulation or by operating your own GSM network that always runs with non-AMR codecs), the new firmware includes a resurrected form of our TCH tap feature, implemented properly this time around. Using the new firmware together with fc-host-tools-r18 or later (the just-released fc-host-tools-r19 version is obviously preferred, but r18 will work too for this purpose), you can capture a complete recording of TCH/FS, TCH/HS or TCH/EFS DL, and then analyze that TCH DL recording (including correct decoding all the way to playable audio) with tools contained in the recently developed and released Themyscira GSM codec libraries & utilities package. You can likewise prepare your own FR and EFR speech recordings and play them into TCH UL with the same tools. Some time later this month (2023-06) I plan on going back to Tijuana (Mexico) with an extra Pirelli DP-L10 phone (on which I can also do all of the above tricks, and which is easier to carry in "field" conditions than a full devboard setup) and a freshly purchased, but still GSM-supporting Telcel SIM, and doing the experiments to see how that Mexican GSM network handles GSM MS that declare themselves as non-AMR-capable. I already know how the not-yet-shutdown network of T-Mobile USA handles such (always prefers AMR, but goes down to EFR if the MS supports EFR but not AMR, or down to FR1 if the MS supports neither AMR nor EFR - but never does HR1), but Telcel MX remains to be tested. I would also be very interested in field reports from other parts of the world: I know we have community members in Western EU and in Russia/Kazakhstan who have FCDEV3B hardware and the necessary GSM tinkerer skill level - how does your country's GSM network act in terms of speech codec selection? Does your network always go for AMR given an AMR-capable MS, or are there any commercial GSM networks anywhere in the world that are natively non-AMR? If your country's network is AMR-native or AMR-preferring, how does it act when the MS declares no AMR support? Does it go down to EFR? Or to HR1? FR1? Are there any commercial GSM networks anywhere in the world that use HR1 codec? Finally, for people who are building new GSM networks (to serve as replacements for those being wrongfully shut down) using Osmocom CNI software, in just under two weeks I will be giving a talk on correct handling of non-AMR (i.e., FR/HR/EFR) speech codecs in Osmocom-based networks: https://osmocom.org/projects/osmo-dev-con/wiki/OsmoDevCall Hasta la Victoria, Siempre, Mychaela aka The Mother _______________________________________________ Community mailing list Community@freecalypso.org https://www.freecalypso.org/mailman/listinfo/community