diff --git a/openbsc/include/openbsc/gsm_data.h b/openbsc/include/openbsc/gsm_data.h
index 84e3c79..700eb73 100644
--- a/openbsc/include/openbsc/gsm_data.h
+++ b/openbsc/include/openbsc/gsm_data.h
@@ -54,6 +54,11 @@
 #define HARDCODED_TSC	7
 #define HARDCODED_BSIC	0x3f	/* NCC = 7 / BCC = 7 */
 
+/* for multi-drop config */
+#define HARDCODED_BTS0_TS	1
+#define HARDCODED_BTS1_TS	6
+#define HARDCODED_BTS2_TS	11
+
 enum gsm_hooks {
 	GSM_HOOK_NM_SWLOAD,
 	GSM_HOOK_RR_PAGING,
diff --git a/openbsc/src/e1_config.c b/openbsc/src/e1_config.c
index d7b4268..8987803 100644
--- a/openbsc/src/e1_config.c
+++ b/openbsc/src/e1_config.c
@@ -30,15 +30,15 @@
 	switch (bts->nr) {
 	case 0:
 		/* First BTS uses E1 TS 01,02,03,04,05 */
-		base_ts = 1 - 1;
+		base_ts = HARDCODED_BTS0_TS - 1;
 		break;
 	case 1:
-		/* Second BTS uses E1 TS 11,12,13,14,15 */
-		base_ts = 11 - 1;
+		/* Second BTS uses E1 TS 06,07,08,09,10 */
+		base_ts = HARDCODED_BTS1_TS - 1;
 		break;
 	case 2:
-		/* Third BTS uses E1 TS 21,22,23,24,25 */
-		base_ts = 21 - 1;
+		/* Third BTS uses E1 TS 11,12,13,14,15 */
+		base_ts = HARDCODED_BTS2_TS - 1;
 	default:
 		return -EINVAL;
 	}