diff --git a/src/gsm_04_08.c b/src/gsm_04_08.c
index 0549076..574e6c1 100644
--- a/src/gsm_04_08.c
+++ b/src/gsm_04_08.c
@@ -622,6 +622,7 @@
 	/* fill the channel information element, this code
 	 * should probably be shared with rsl_rx_chan_rqd() */
 	cmm->chan_desc.chan_nr = lchan2chan_nr(lchan);
+	cmm->chan_desc.h0.tsc = lchan->ts->trx->bts->tsc;
 	cmm->chan_desc.h0.h = 0;
 	cmm->chan_desc.h0.arfcn_high = arfcn >> 8;
 	cmm->chan_desc.h0.arfcn_low = arfcn & 0xff;