diff --git a/openbsc/src/libbsc/abis_om2000.c b/openbsc/src/libbsc/abis_om2000.c
index 1fb7689..9bf0fe2 100644
--- a/openbsc/src/libbsc/abis_om2000.c
+++ b/openbsc/src/libbsc/abis_om2000.c
@@ -1654,6 +1654,7 @@
 
 static void om2k_mo_st_wait_enable_accept(struct osmo_fsm_inst *fi, uint32_t event, void *data)
 {
+	struct om2k_mo_fsm_priv *omfp = fi->priv;
 	struct om2k_decoded_msg *omd = data;
 
 	switch (omd->msg_type) {
@@ -1661,6 +1662,9 @@
 		osmo_fsm_inst_state_chg(fi, OM2K_ST_ERROR, 0, 0);
 		break;
 	case OM2K_MSGT_ENABLE_REQ_ACK:
+		if (omfp->mo->addr.class == OM2K_MO_CLS_IS &&
+		    omfp->trx->bts->rbs2000.use_superchannel)
+			e1inp_ericsson_set_altc(omfp->trx->bts->oml_link->ts->line, 1);
 		osmo_fsm_inst_state_chg(fi, OM2K_ST_WAIT_ENABLE_RES,
 					OM2K_TIMEOUT, 0);
 	}