diff --git a/bts/BTS_Tests.ttcn b/bts/BTS_Tests.ttcn
index a2d4ca42d..fe0a9338e 100644
--- a/bts/BTS_Tests.ttcn
+++ b/bts/BTS_Tests.ttcn
@@ -313,17 +313,29 @@ function f_init(charstring id := "BTS-Test") runs on test_CT {
 		valueof(ts_RslChanNr_SDCCH8(6,4)), valueof(ts_RslChanNr_SDCCH8(6,5)),
 		valueof(ts_RslChanNr_SDCCH8(6,6)), valueof(ts_RslChanNr_SDCCH8(6,7))
 	};
-	g_AllChanTypes := {
-		/* TS 1..4: TCH/F */
-		valueof(ts_RslChanNr_Bm(1)),
-		/* TS 5: TCH/H */
-		valueof(ts_RslChanNr_Lm(5,1)),
-		/* TS 0: SDCCH/4 */
-		valueof(ts_RslChanNr_SDCCH4(0,2)),
-		/* TS 6: SDCCH/8 */
-		valueof(ts_RslChanNr_SDCCH8(6,4))
-	};
 
+	/* FIXME: FACCH/H is unreliable with calypso firmware, see OS#3653 */
+	if (mp_bb_trxc_port != -1) {
+		g_AllChanTypes := {
+			/* TS 1..4: TCH/F */
+			valueof(ts_RslChanNr_Bm(1)),
+			/* TS 5: TCH/H */
+			valueof(ts_RslChanNr_Lm(5,1)),
+			/* TS 0: SDCCH/4 */
+			valueof(ts_RslChanNr_SDCCH4(0,2)),
+			/* TS 6: SDCCH/8 */
+			valueof(ts_RslChanNr_SDCCH8(6,4))
+		};
+	} else {
+		g_AllChanTypes := {
+			/* TS 1..4: TCH/F */
+			valueof(ts_RslChanNr_Bm(1)),
+			/* TS 0: SDCCH/4 */
+			valueof(ts_RslChanNr_SDCCH4(0,2)),
+			/* TS 6: SDCCH/8 */
+			valueof(ts_RslChanNr_SDCCH8(6,4))
+		};
+	}
 	f_init_rsl(id);
 	T.start;
 	alt {