I deduct that " #if defined(L1_HAS_EFR) && defined(USE_L1_RTP_MODE) " is why I'm seeing this message logged, but it seems to be #define... Any pointers, ideas ? This doesn't seem like a configuration thing, but a compilation time option? I'd have expected that EFR is fully supported? osmo-bts.cfg snippet ------------------------------ bts 0 band 850 ipa unit-id 1801 0 oml remote-ip 127.0.0.1 rtp jitter-buffer 100 paging queue-size 200 paging lifetime 0 trx 0 clock-calibration 603 trx-calibration-path (null) clock-source ocxo uplink-power-target -75 min-qual-rach -5 min-qual-norm -5 Regards, Roelf. --bcaec51b1b6f7f08e204e11a4392 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable <div>I have FINALLY gotten to play with my sysmoBTS acquired many months ag= o, and updated to the latest packages using okpg, and am running a NITB.</d= iv><div><br></div><div>GSM850 test setup in open mode A5/0, and I can SMS a= nd call between devices.</div> <div><br></div><div>However, there is no audio, and BTS console logs report= s many repeats of the following during an established call.</div><div><br><= /div><0006> tch.c:601 (bts=3D0,trx=3D0,ts=3D7,ss=3D0) Rx Payload Type= EFR is unsupported<div> <0006> tch.c:601 (bts=3D0,trx=3D0,ts=3D7,ss=3D0) Rx Payload Type EFR = is unsupported</div><div><0006> tch.c:601 (bts=3D0,trx=3D0,ts=3D7,ss= =3D0) Rx Payload Type EFR is unsupported</div><div><br><div><br></div><div>=