diff --git a/include/osmocom/abis/e1_input.h b/include/osmocom/abis/e1_input.h
index 79455e1..f9b4850 100644
--- a/include/osmocom/abis/e1_input.h
+++ b/include/osmocom/abis/e1_input.h
@@ -201,6 +201,8 @@
 	struct e1inp_driver *driver;
 	void *driver_data;
 };
+#define e1inp_line_ipa_oml_ts(line) (&line->ts[0])
+#define e1inp_line_ipa_rsl_ts(line, trx_id) (&line->ts[1 + (trx_id)])
 
 /* SS_L_INPUT signals */
 enum e1inp_signal_input {
diff --git a/src/input/ipaccess.c b/src/input/ipaccess.c
index f8e8e09..8c02996 100644
--- a/src/input/ipaccess.c
+++ b/src/input/ipaccess.c
@@ -62,8 +62,11 @@
 static int ipaccess_drop(struct osmo_fd *bfd, struct e1inp_line *line)
 {
 	int ret = 1;
-	unsigned int ts_nr = bfd->priv_nr;
-	struct e1inp_ts *e1i_ts = &line->ts[ts_nr-1];
+	struct e1inp_ts *e1i_ts;
+	if (bfd->priv_nr == E1INP_SIGN_OML)
+		e1i_ts = e1inp_line_ipa_oml_ts(line);
+	else
+		e1i_ts = e1inp_line_ipa_rsl_ts(line, bfd->priv_nr - E1INP_SIGN_RSL);
 
 	/* Error case: we did not see any ID_RESP yet for this socket. */
 	if (bfd->fd != -1) {
@@ -185,7 +188,7 @@
 			 * this RSL link, attach it to this socket. */
 			bfd->data = new_line = sign_link->ts->line;
 			e1inp_line_get(new_line);
-			ts = &new_line->ts[E1INP_SIGN_RSL+unit_data.trx_id-1];
+			ts = e1inp_line_ipa_rsl_ts(new_line, unit_data.trx_id);
 			newbfd = &ts->driver.ipaccess.fd;
 
 			/* get rid of our old temporary bfd */
@@ -223,12 +226,17 @@
 {
 	struct e1inp_line *line = bfd->data;
 	unsigned int ts_nr = bfd->priv_nr;
-	struct e1inp_ts *e1i_ts = &line->ts[ts_nr-1];
+	struct e1inp_ts *e1i_ts;
 	struct e1inp_sign_link *link;
 	struct ipaccess_head *hh;
 	struct msgb *msg = NULL;
 	int ret, rc;
 
+	if (bfd->priv_nr == E1INP_SIGN_OML)
+		e1i_ts = e1inp_line_ipa_oml_ts(line);
+	else
+		e1i_ts = e1inp_line_ipa_rsl_ts(line, bfd->priv_nr - E1INP_SIGN_RSL);
+
 	ret = ipa_msg_recv_buffered(bfd->fd, &msg, &e1i_ts->pending_msg);
 	if (ret < 0) {
 		if (ret == -EAGAIN)
@@ -312,11 +320,16 @@
 static int __handle_ts1_write(struct osmo_fd *bfd, struct e1inp_line *line)
 {
 	unsigned int ts_nr = bfd->priv_nr;
-	struct e1inp_ts *e1i_ts = &line->ts[ts_nr-1];
+	struct e1inp_ts *e1i_ts;
 	struct e1inp_sign_link *sign_link;
 	struct msgb *msg;
 	int ret;
 
+	if (bfd->priv_nr == E1INP_SIGN_OML)
+		e1i_ts = e1inp_line_ipa_oml_ts(line);
+	else
+		e1i_ts = e1inp_line_ipa_rsl_ts(line, bfd->priv_nr - E1INP_SIGN_RSL);
+
 	bfd->when &= ~BSC_FD_WRITE;
 
 	/* get the next msg for this timeslot */
@@ -454,7 +467,6 @@
 static int ipaccess_bsc_oml_cb(struct ipa_server_link *link, int fd)
 {
 	int ret;
-	int idx = 0;
 	int i;
 	struct e1inp_line *line;
 	struct e1inp_ts *e1i_ts;
@@ -468,13 +480,13 @@
 	}
 
 	/* create virrtual E1 timeslots for signalling */
-	e1inp_ts_config_sign(&line->ts[E1INP_SIGN_OML-1], line);
+	e1inp_ts_config_sign(e1inp_line_ipa_oml_ts(line), line);
 
 	/* initialize the fds */
 	for (i = 0; i < ARRAY_SIZE(line->ts); ++i)
 		line->ts[i].driver.ipaccess.fd.fd = -1;
 
-	e1i_ts = &line->ts[idx];
+	e1i_ts = e1inp_line_ipa_oml_ts(line);
 
 	bfd = &e1i_ts->driver.ipaccess.fd;
 	osmo_fd_setup(bfd, fd, BSC_FD_READ, ipaccess_fd_cb, line, E1INP_SIGN_OML);
@@ -524,9 +536,9 @@
 
 	/* we need this to initialize this in case to avoid crashes in case
 	 * that the socket is closed before we've seen an ID_RESP. */
-	e1inp_ts_config_sign(&line->ts[E1INP_SIGN_OML-1], line);
+	e1inp_ts_config_sign(e1inp_line_ipa_oml_ts(line), line);
 
-	e1i_ts = &line->ts[E1INP_SIGN_RSL-1];
+	e1i_ts = e1inp_line_ipa_rsl_ts(line, 0);
 
 	bfd = &e1i_ts->driver.ipaccess.fd;
 	osmo_fd_setup(bfd, fd, BSC_FD_READ, ipaccess_fd_cb, line, E1INP_SIGN_RSL);
@@ -763,9 +775,9 @@
 		msgb_free(msg);
 		return ret;
 	} else if (link->port == IPA_TCP_PORT_OML)
-		e1i_ts = &link->line->ts[0];
+		e1i_ts = e1inp_line_ipa_oml_ts(link->line);
 	else if (link->port == IPA_TCP_PORT_RSL)
-		e1i_ts = &link->line->ts[link->ofd->priv_nr-1];
+		e1i_ts = e1inp_line_ipa_rsl_ts(link->line, link->ofd->priv_nr - E1INP_SIGN_RSL);
 
 	OSMO_ASSERT(e1i_ts != NULL);
 
@@ -870,7 +882,7 @@
 		     IPA_TCP_PORT_OML);
 
 		link = ipa_client_conn_create(tall_ipa_ctx,
-					      &line->ts[E1INP_SIGN_OML-1],
+					      e1inp_line_ipa_oml_ts(line),
 					      E1INP_SIGN_OML,
 					      line->ops->cfg.ipa.addr,
 					      IPA_TCP_PORT_OML,
@@ -920,7 +932,7 @@
 	}
 
 	rsl_link = ipa_client_conn_create(tall_ipa_ctx,
-					  &line->ts[E1INP_SIGN_RSL+trx_nr-1],
+					  e1inp_line_ipa_rsl_ts(line, trx_nr),
 					  E1INP_SIGN_RSL+trx_nr,
 					  rem_addr, rem_port,
 					  ipaccess_bts_updown_cb,
diff --git a/tests/e1inp_ipa_bsc_test.c b/tests/e1inp_ipa_bsc_test.c
index 9064d0a..a7317f8 100644
--- a/tests/e1inp_ipa_bsc_test.c
+++ b/tests/e1inp_ipa_bsc_test.c
@@ -30,9 +30,9 @@
 	switch(type) {
 	case E1INP_SIGN_OML:
 		LOGP(DBSCTEST, LOGL_NOTICE, "OML link up request received.\n");
-		e1inp_ts_config_sign(&line->ts[E1INP_SIGN_OML - 1], line);
+		e1inp_ts_config_sign(e1inp_line_ipa_oml_ts(line), line);
 		sign_link = oml_sign_link =
-			e1inp_sign_link_create(&line->ts[E1INP_SIGN_OML - 1],
+			e1inp_sign_link_create(e1inp_line_ipa_oml_ts(line),
 					       E1INP_SIGN_OML, NULL, 255, 0);
 		break;
 	case E1INP_SIGN_RSL:
@@ -45,10 +45,10 @@
 
 		/* We have to use the same line that the OML link. */
 		oml_line = oml_sign_link->ts->line;
-		e1inp_ts_config_sign(&oml_line->ts[E1INP_SIGN_RSL - 1],
+		e1inp_ts_config_sign(e1inp_line_ipa_rsl_ts(oml_line, 0),
 				     oml_line);
 		sign_link = rsl_sign_link =
-		     e1inp_sign_link_create(&oml_line->ts[E1INP_SIGN_RSL - 1],
+		     e1inp_sign_link_create(e1inp_line_ipa_rsl_ts(oml_line, 0),
 					    E1INP_SIGN_RSL, NULL, 0, 0);
 		break;
 	default:
diff --git a/tests/e1inp_ipa_bts_test.c b/tests/e1inp_ipa_bts_test.c
index 48a5c59..10fe0e8 100644
--- a/tests/e1inp_ipa_bts_test.c
+++ b/tests/e1inp_ipa_bts_test.c
@@ -51,9 +51,9 @@
 	case E1INP_SIGN_OML:
 		LOGP(DBTSTEST, LOGL_NOTICE, "OML link up request received.\n");
 
-		e1inp_ts_config_sign(&line->ts[E1INP_SIGN_OML - 1], line);
+		e1inp_ts_config_sign(e1inp_line_ipa_oml_ts(line), line);
 		sign_link = oml_sign_link =
-			e1inp_sign_link_create(&line->ts[E1INP_SIGN_OML - 1],
+			e1inp_sign_link_create(e1inp_line_ipa_oml_ts(line),
 						E1INP_SIGN_OML, NULL, 255, 0);
 		if (!oml_sign_link) {
 			LOGP(DBTSTEST, LOGL_ERROR,
@@ -76,10 +76,10 @@
 	case E1INP_SIGN_RSL:
 		LOGP(DBTSTEST, LOGL_NOTICE, "RSL link up request received.\n");
 
-		e1inp_ts_config_sign(&line->ts[E1INP_SIGN_RSL - 1], line);
+		e1inp_ts_config_sign(e1inp_line_ipa_rsl_ts(line, 0), line);
 
 		sign_link = rsl_sign_link =
-			e1inp_sign_link_create(&line->ts[E1INP_SIGN_RSL - 1],
+			e1inp_sign_link_create(e1inp_line_ipa_rsl_ts(line, 0),
 						E1INP_SIGN_RSL, NULL, 0, 0);
 		if (!rsl_sign_link) {
 			LOGP(DBTSTEST, LOGL_ERROR,