This is merely a historical archive of years 2008-2021, before the migration to mailman3.
A maintained and still updated list archive can be found at https://lists.osmocom.org/hyperkitty/list/OpenBSC@lists.osmocom.org/.
Neels Hofmeyr nhofmeyr at sysmocom.deOn Mon, May 29, 2017 at 03:29:49PM +0200, Harald Welte wrote: > Voice testing has always been on the wishlist, but further down on the > TODO list. One issue here is that > > a) many modems don't do voice at all (data-only modems for laptops) > b) some modems expose voice only as analog audio (difficult to interface, > would require custom hardware next to the modem, e.g. using USB > soundcard, calibrate the levels, ...) > c) some modems expose the voice as PCM bus. Similarly, would require > some external codec chip and/or USB soundcard or the like, plus a > custom circuit > d) some modems expose voice as "GSM codec frames over UART" or other > highty proprietary formats > e) some modems expose voice as USB audio device. Most convenient, but > only found in some Qualcomm LE based devices such as Sierra Wireless > or Quectel. For the record, Harald already knows this: Another issue is that we don't have a modem yet for which ofono offers even the possibility of initiating a call. It would be nice to at first have the voice signalling to begin with. > simpler: Every phone is supposed to include a voice loop-back mode. In Hah interesting feat! I wonder whether it is sending the exact RTP packets back. This way we can certainly play around with the RF attenuation and see whether voice frames got dropped and so forth. Sounds like we would initiate a single-leg call from the MSC with the modem in loopback mode. But we could maybe also still call one modem from the other, and tell one of them to go in loopback mode? Anyhow, sounds quite interesting. > The idea is that one puts a special "Test SIM" (as specified in TS > 51.010-1 Annex 4, where EF.AD first byte == 0x80 is the criteria in this > context) into the phone, and then sends some specific commands on Layer3 > to activate the loop. Hopefully we can tell the sysmoUSIM to do this, and thus still use all other features like authentication? > downlink (minus some occasional bit error, but those should be super low > given we're operating omso-gsm-tester over coaxial cabling between MS and > BTS). Unless we do want to turn up the attenuation and see how, say, handovers go. ~N -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 819 bytes Desc: Digital signature URL: <http://lists.osmocom.org/pipermail/openbsc/attachments/20170529/5d9c81b2/attachment.bin>