diff --git a/openbsc/include/openbsc/abis_nm.h b/openbsc/include/openbsc/abis_nm.h
index 946d237..ab4b1ce 100644
--- a/openbsc/include/openbsc/abis_nm.h
+++ b/openbsc/include/openbsc/abis_nm.h
@@ -696,6 +696,8 @@
 			 u_int8_t test_nr, u_int8_t auton_report,
 			 u_int8_t *phys_config, u_int16_t phys_config_len);
 
+int abis_nm_chcomb4pchan(enum gsm_phys_chan_config pchan);
+
 /* Siemens / BS-11 specific */
 int abis_nm_bs11_reset_resource(struct gsm_bts *bts);
 int abis_nm_bs11_db_transmission(struct gsm_bts *bts, int begin);
diff --git a/openbsc/src/abis_nm.c b/openbsc/src/abis_nm.c
index 8fcfdba..a75ef7a 100644
--- a/openbsc/src/abis_nm.c
+++ b/openbsc/src/abis_nm.c
@@ -404,6 +404,23 @@
 	},
 };
 
+static const enum abis_nm_chan_comb chcomb4pchan[] = {
+	[GSM_PCHAN_CCCH]	= NM_CHANC_mainBCCH,
+	[GSM_PCHAN_CCCH_SDCCH4]	= NM_CHANC_BCCHComb,
+	[GSM_PCHAN_TCH_F]	= NM_CHANC_TCHFull,
+	[GSM_PCHAN_TCH_H]	= NM_CHANC_TCHHalf,
+	[GSM_PCHAN_SDCCH8_SACCH8C] = NM_CHANC_SDCCH,
+	/* FIXME: bounds check */
+};
+
+int abis_nm_chcomb4pchan(enum gsm_phys_chan_config pchan)
+{
+	if (pchan < ARRAY_SIZE(chcomb4pchan))
+		return chcomb4pchan[pchan];
+
+	return -EINVAL;
+}
+
 int abis_nm_tlv_parse(struct tlv_parsed *tp, const u_int8_t *buf, int len)
 {
 	return tlv_parse(tp, &nm_att_tlvdef, buf, len, 0, 0);
diff --git a/openbsc/src/chan_alloc.c b/openbsc/src/chan_alloc.c
index 5d1e137..039fccf 100644
--- a/openbsc/src/chan_alloc.c
+++ b/openbsc/src/chan_alloc.c
@@ -53,15 +53,6 @@
 	return ts;
 }
 
-static const enum abis_nm_chan_comb chcomb4pchan[] = {
-	[GSM_PCHAN_CCCH]	= NM_CHANC_mainBCCH,
-	[GSM_PCHAN_CCCH_SDCCH4]	= NM_CHANC_BCCHComb,
-	[GSM_PCHAN_TCH_F]	= NM_CHANC_TCHFull,
-	[GSM_PCHAN_TCH_H]	= NM_CHANC_TCHHalf,
-	[GSM_PCHAN_SDCCH8_SACCH8C] = NM_CHANC_SDCCH,
-	/* FIXME: bounds check */
-};
-
 /* Allocate a physical channel (TS) */
 struct gsm_bts_trx_ts *ts_alloc(struct gsm_bts *bts,
 				enum gsm_phys_chan_config pchan)
@@ -108,7 +99,7 @@
 			if (ts->pchan == GSM_PCHAN_NONE) {
 				ts->pchan = pchan;
 				/* set channel attribute on OML */
-				abis_nm_set_channel_attr(ts, chcomb4pchan[pchan]);
+				abis_nm_set_channel_attr(ts, abis_nm_chcomb4pchan(pchan));
 				return ts;
 			}
 		}