diff --git a/openbsc/src/abis_rsl.c b/openbsc/src/abis_rsl.c
index cc4a229..394d98e 100644
--- a/openbsc/src/abis_rsl.c
+++ b/openbsc/src/abis_rsl.c
@@ -1044,7 +1044,7 @@
 	ia.chan_desc.h0.h = 0;
 	ia.chan_desc.h0.arfcn_high = arfcn >> 8;
 	ia.chan_desc.h0.arfcn_low = arfcn & 0xff;
-	ia.chan_desc.h0.tsc = 7;
+	ia.chan_desc.h0.tsc = bts->tsc;
 	/* use request reference extracted from CHAN_RQD */
 	memcpy(&ia.req_ref, rqd_ref, sizeof(ia.req_ref));
 	ia.timing_advance = rqd_ta;